doc: board: apple: Update Apple M1 documentation

U-Boot now supports NVMe storage and on the laptop models, the
SPI keyboard.  Since we now disable the debug console by default
provide instructions on how the enable the debug console including
a table listing the appropriate UART base address for each of the
supported SoCs.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
1 file changed