msm8x60_celox: Remove panel-undervolt interface

Nobody seemed to care about it anyway, so no reason to keep it and keep tweaking it.

Signed-off-by: Sultanxda <sultanxda@gmail.com>
mdp4_overlay: Make sure ion_map_iommu() is successful for all domains all the time

Signed-off-by: Sultanxda <sultanxda@gmail.com>
Sultan_defconfig: v1.2.1