Make driver generic for multiple ILI displays. The adopted strategy is
to share all driver code except register initialization, which has been
found to have some specific registers/values depending on the
controller.
The driver has been adjusted to support multiple compatibles.
Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
Move pixel format setting (RGB565/RGB888) to DeviceTree. Add support for
changing pixel format at runtime.
Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>