Ian Ray authored Aug 30, 2019 and Bob Beckett committed Dec 12, 2019

Enable DM_VIDEO for mx53ppd.  This also requires DM_REGULATOR_FIXED and
DM_PWM for the backlight, and `failbootcmd' is changed to use lcdputs.

Remove unused MX53PPD_LCD_POWER.
Remove old (incorrect) setup_iomux_lcd.
Enable backlight via display enable handler.
Use cls command to initiate display in HW agnostic manner.

Signed-off-by: Ian Ray <ian.ray@ge.com>