drm: zynq_drm: encoder/plane: Change the order of configuration

Change the order of configuration from input to output based on
the OSD product guide. + set global alpha to 0xff

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: crtc/plane: Run without OSD

This patch makes zynq_drm runs without OSD. If there's an
OSD, zynq_plane configures the OSD layer, on the other hand,
if there's no OSD, zynq_plane runs with only VDMA without
setting the OSD.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
arm: boot: dts: zynq-zc702-drm: Remove unused VTC node

A vtc node is not used, so removed.

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