drm/mediatek: add memory mode and layer_config for RDMA

This patch add memory mode for RDMA and layer_config for RDMA

If use RDMA to read data from memory, it should set memory mode to RDMA

Layer config set the data address and pitch to RDMA from plane setting.

Signed-off-by: Stu Hsieh <stu.hsieh@mediatek.com>
Signed-off-by: CK Hu <ck.hu@mediatek.com>