arm: mx6: cm-fx6: map HDMI to IPU1 DI0 explicitly

arm: mx6: cm-fx6: map HDMI to IPU1 DI0 explicitly

U-Boot does not explicitly assign the display to an IPU interface. Instead, it
relies on the power-on default of DI0.

Since the kernel reassigns HDMI display to DI1, after a warm reset the HDMI
display no longer works in U-Boot.

Fix this by explicitly assigning HDMI to IPU1 DI0 in U-Boot.

Cc: Stefano Babic <[email protected]>
Cc: Igor Grinberg <[email protected]>
Signed-off-by: Nikita Kiryanov <[email protected]>
Acked-by: Igor Grinberg <[email protected]>