drm: atmel-hlcdc: add driver ops to differentiate HLCDC and XLCDC IP

Add LCD IP specific ops in driver data to differentiate
HLCDC and XLCDC code within the atmel-hlcdc driver files.
XLCDC in SAM9X7 has different sets of registers and additional
configuration bits when compared to previous HLCDC IP. Read/write
operation on the controller register and functionality is now
separated using the LCD IP specific ops.

Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240424053351.589830-2-manikandan.m@microchip.com