v4l: xilinx-demosaic: Make max width and height properties mandatory

v4l: xilinx-demosaic: Make max width and height properties mandatory

This patch makes xlnx,max-width and xlnx,max-height dt properties
mandatory. It breaks backward compatibility and has a warning message
for this.

Signed-off-by: Vishal Sagar <vishal.sagar@xilinx.com>
Reviewed-by: Hyun Kwon <hyun.kwon@xilinx.com>