mx6ull: Handle the CONFIG_MX6ULL cases correctly

mx6ull: Handle the CONFIG_MX6ULL cases correctly

Since commit 051ba9e082f7 ("Kconfig: mx6ull: Deselect MX6UL from
CONFIG_MX6ULL") CONFIG_MX6ULL does not select CONFIG_MX6UL anymore, so
take this into consideration in all the checks for CONFIG_MX6UL.

This fixes a boot regression.

Reported-by: Stefan Agner <[email protected]>
Signed-off-by: Fabio Estevam <[email protected]>
Reviewed-by: Stefan Agner <[email protected]>
Tested-by: Breno Lima <[email protected]>
Tested-by: Peng Fan <[email protected]>
Reviewed-by: Stefano Babic <[email protected]>
Tested-by: Jörg Krause <[email protected]>