esp8266/uart: Properly initialise UART0 RXD pin in uart_config.
esp8266/uart: Properly initialise UART0 RXD pin in uart_config.

Tested and seems to work.  See #1995.

TDAbboud/micropython,blazewicz/micropython,emfcamp/micropython,AriZuu/micropython,Timmenem/micropython,mhoffma/micropython,trezor/micropython,hosaka/micropython,tralamazza/micropython,ryannathans/micropython,blazewicz/micropython,AriZuu/micropython,tuc-osg/micropython,redbear/micropython,HenrikSolver/micropython,dxxb/micropython,tralamazza/micropython,HenrikSolver/micropython,PappaPeppar/micropython,dxxb/micropython,dinau/micropython,dxxb/micropython,infinnovation/micropython,tobbad/micropython,adafruit/circuitpython,alex-robbins/micropython,torwag/micropython,dinau/micropython,dmazzella/micropython,SHA2017-badge/micropython-esp32,alex-march/micropython,pozetroninc/micropython,MrSurly/micropython,MrSurly/micropython-esp32,HenrikSolver/micropython,infinnovation/micropython,toolmacher/micropython,micropython/micropython-esp32,hiway/micropython,pramasoul/micropython,AriZuu/micropython,matthewelse/micropython,ganshun666/micropython,trezor/micropython,dmazzella/micropython,hosaka/micropython,trezor/micropython,pramasoul/micropython,turbinenreiter/micropython,Timmenem/micropython,adafruit/circuitpython,pfalcon/micropython,kerneltask/micropython,MrSurly/micropython-esp32,redbear/micropython,hiway/micropython,ganshun666/micropython,alex-march/micropython,tuc-osg/micropython,TDAbboud/micropython,pramasoul/micropython,turbinenreiter/micropython,puuu/micropython,Peetz0r/micropython-esp32,MrSurly/micropython-esp32,tuc-osg/micropython,jmarcelino/pycom-micropython,pfalcon/micropython,PappaPeppar/micropython,trezor/micropython,adafruit/micropython,matthewelse/micropython,redbear/micropython,lowRISC/micropython,oopy/micropython,lowRISC/micropython,mpalomer/micropython,TDAbboud/micropython,HenrikSolver/micropython,adafruit/micropython,alex-march/micropython,puuu/micropython,ganshun666/micropython,blazewicz/micropython,trezor/micropython,ryannathans/micropython,Peetz0r/micropython-esp32,MrSurly/micropython-esp32,adafruit/micropython,hosaka/micropython,oopy/micropython,dinau/micropython,chrisdearman/micropython,matthewelse/micropython,kerneltask/micropython,emfcamp/micropython,kerneltask/micropython,cwyark/micropython,chrisdearman/micropython,dinau/micropython,MrSurly/micropython,tobbad/micropython,bvernoux/micropython,ganshun666/micropython,dinau/micropython,pramasoul/micropython,cwyark/micropython,chrisdearman/micropython,deshipu/micropython,adafruit/micropython,hiway/micropython,PappaPeppar/micropython,pozetroninc/micropython,tralamazza/micropython,torwag/micropython,ryannathans/micropython,pfalcon/micropython,emfcamp/micropython,deshipu/micropython,pfalcon/micropython,hosaka/micropython,tuc-osg/micropython,tobbad/micropython,redbear/micropython,ryannathans/micropython,PappaPeppar/micropython,swegener/micropython,MrSurly/micropython,pozetroninc/micropython,alex-march/micropython,bvernoux/micropython,MrSurly/micropython,hosaka/micropython,adafruit/circuitpython,lowRISC/micropython,matthewelse/micropython,turbinenreiter/micropython,tobbad/micropython,oopy/micropython,alex-robbins/micropython,toolmacher/micropython,mhoffma/micropython,alex-march/micropython,ganshun666/micropython,deshipu/micropython,tralamazza/micropython,deshipu/micropython,MrSurly/micropython,dmazzella/micropython,mhoffma/micropython,jmarcelino/pycom-micropython,hiway/micropython,MrSurly/micropython-esp32,adafruit/circuitpython,deshipu/micropython,matthewelse/micropython,emfcamp/micropython,cwyark/micropython,selste/micropython,adafruit/circuitpython,oopy/micropython,TDAbboud/micropython,SHA2017-badge/micropython-esp32,puuu/micropython,dmazzella/micropython,bvernoux/micropython,dxxb/micropython,pozetroninc/micropython,chrisdearman/micropython,AriZuu/micropython,cwyark/micropython,TDAbboud/micropython,infinnovation/micropython,Timmenem/micropython,turbinenreiter/micropython,micropython/micropython-esp32,swegener/micropython,henriknelson/micropython,oopy/micropython,bvernoux/micropython,adafruit/circuitpython,bvernoux/micropython,kerneltask/micropython,mpalomer/micropython,micropython/micropython-esp32,emfcamp/micropython,AriZuu/micropython,SHA2017-badge/micropython-esp32,mpalomer/micropython,micropython/micropython-esp32,henriknelson/micropython,kerneltask/micropython,lowRISC/micropython,toolmacher/micropython,swegener/micropython,selste/micropython,ryannathans/micropython,swegener/micropython,torwag/micropython,micropython/micropython-esp32,henriknelson/micropython,dxxb/micropython,Peetz0r/micropython-esp32,mpalomer/micropython,alex-robbins/micropython,blazewicz/micropython,redbear/micropython,selste/micropython,matthewelse/micropython,torwag/micropython,alex-robbins/micropython,SHA2017-badge/micropython-esp32,toolmacher/micropython,tobbad/micropython,hiway/micropython,blazewicz/micropython,henriknelson/micropython,PappaPeppar/micropython,chrisdearman/micropython,mhoffma/micropython,infinnovation/micropython,Peetz0r/micropython-esp32,swegener/micropython,toolmacher/micropython,tuc-osg/micropython,cwyark/micropython,mhoffma/micropython,lowRISC/micropython,mpalomer/micropython,Peetz0r/micropython-esp32,Timmenem/micropython,selste/micropython,jmarcelino/pycom-micropython,selste/micropython,Timmenem/micropython,HenrikSolver/micropython,infinnovation/micropython,pozetroninc/micropython,adafruit/micropython,jmarcelino/pycom-micropython,puuu/micropython,henriknelson/micropython,pfalcon/micropython,torwag/micropython,turbinenreiter/micropython,alex-robbins/micropython,SHA2017-badge/micropython-esp32,jmarcelino/pycom-micropython,pramasoul/micropython,puuu/micropython