rework the stm32mp1 integration

[texierp]

No description provided.

[jorisoffouga]

Please write more infomations for rework

[texierp]

Since the stmp32mp1 uses the distro boot, we can use the devplist to indicate from which partition the extlinux.conf is read instead of using a custom boot script.

To do this, a new entry is needed in sw-description for the scan_dev_for_boot_part, you can check [0] for further informations.

Also, keep in mind that we have to override the default extlinux.conf with something like this:

UBOOT_EXTLINUX_ROOT = "root=/dev/mmcblk0p${devplist}" (not tested)

Voilà ;)

[0] - https://github.com/sbabic/meta-swupdate-boards/blob/master/recipes-extended/images/update-image/wandboard/sw-description#L34