uboot-imx6: bump to 2021.01 release

uboot-imx6: bump to 2021.01 release

Refreshed all patches, removed 110-mx6cuboxi-mmc-fallback.patch as it
seems, that upstream has probably added similar funcionality in commit
6c3fbf3e456c ("mx6cuboxi: customize board_boot_order to access eMMC")
and it needs to be re-verified by device owner.

Run tested on apalis.

Cc: Felix Fietkau <[email protected]>
Cc: Vladimir Vid <[email protected]>
Cc: Tim Harvey <[email protected]>
Cc: Koen Vandeputte <[email protected]>
Signed-off-by: Petr Štetiar <[email protected]>