nrf/modules/machine/adc: Don't compare -1 to an unsigned number.
nrf/modules/machine/adc: Don't compare -1 to an unsigned number.

Clang warns about this.

pfalcon/micropython,MrSurly/micropython,pfalcon/micropython,trezor/micropython,kerneltask/micropython,pfalcon/micropython,adafruit/circuitpython,henriknelson/micropython,tobbad/micropython,pramasoul/micropython,kerneltask/micropython,MrSurly/micropython,henriknelson/micropython,selste/micropython,bvernoux/micropython,pozetroninc/micropython,pramasoul/micropython,pramasoul/micropython,adafruit/circuitpython,trezor/micropython,pramasoul/micropython,pozetroninc/micropython,henriknelson/micropython,MrSurly/micropython,selste/micropython,henriknelson/micropython,selste/micropython,henriknelson/micropython,adafruit/circuitpython,pfalcon/micropython,MrSurly/micropython,adafruit/circuitpython,kerneltask/micropython,tobbad/micropython,pozetroninc/micropython,trezor/micropython,trezor/micropython,bvernoux/micropython,pramasoul/micropython,tobbad/micropython,trezor/micropython,tobbad/micropython,bvernoux/micropython,kerneltask/micropython,selste/micropython,bvernoux/micropython,pfalcon/micropython,adafruit/circuitpython,pozetroninc/micropython,kerneltask/micropython,pozetroninc/micropython,bvernoux/micropython,MrSurly/micropython,selste/micropython,adafruit/circuitpython,tobbad/micropython