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 <nbd@nbd.name>
Cc: Vladimir Vid <vladimir.vid@sartura.hr>
Cc: Tim Harvey <tharvey@gateworks.com>
Cc: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz>