imx: imx-common: power down lcdif before boot os

imx: imx-common: power down lcdif before boot os

Need to call lcdif_power_down to make lcdif in initial state
before kernel boot. Similar issue for uboot reset with lcdif
enabled, system will hang after serveral times resetting. Need
to let lcdif initial state to make all go well.

Signed-off-by: Peng Fan <[email protected]>
Cc: Stefano Babic <[email protected]>
Cc: Eric Nelson <[email protected]>
Cc: Nikita Kiryanov <[email protected]>
Cc: Tim Harvey <[email protected]>
Cc: Fabio Estevam <[email protected]>