Load env from eMMC boot partition
This merge request moves the environment to the eMMC boot1 hwpart, and optionally allows to board to automatically select the hwpart at runtime based on the current eMMC boot config.
This is required to implement librem5-devkit-tools#10
The changes have been done on the Librem5 devkit board created in !7 (merged)
Edited by Hugo Grostabussiat