drm: zynq_drm: osd: Add a osd driver

Add a driver for OSD(On-Screen-Display). This IP has alpha
blending feature with multiple layers(max=8), so it can be
used to enable KMS planes.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: plane: Add plane functions

KMS plane support is added. This plane implementation uses
OSD functions to enable multi plane support. VDMA, and OSD
are handled in plane.c which were done in crtc.c. Instead
crtc is given a private plane which is not exposed to other clients.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: drv: Add OSD/PLANE definition

Add OSD/PLANE definition to debug function. + some minor changes.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: crtc: Apply plane support

This applies the plane support to crtc.c and adds OSD/VDMA to
device trees. The plane support is tested using xlnxtest with
plane support test. This is the first working version, and still
has some known issues.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>