drm: atmel-hlcdc: add DPI mode support for XLCDC

Add support for Display Pixel Interface (DPI) Compatible Mode
support in atmel-hlcdc driver for XLCDC IP along with legacy
pixel mapping. DPI mode BIT is configured in LCDC_CFG5 register.

Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
[durai.manickamkr@microchip.com: update DPI mode bit using is_xlcdc flag]
Signed-off-by: Durai Manickam KR <durai.manickamkr@microchip.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240424053351.589830-6-manikandan.m@microchip.com