stm32/boards/stm32h743.ld: Fix total flash size, should be 2048k.
stm32/boards/stm32h743.ld: Fix total flash size, should be 2048k.

Fixes issue #4240.

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