Radeon/AMDGPU X.Org Drivers Add TILE Property Support For Tiled Monitors

It's coming a bit late considering the X.Org Server bits were added back in 2015 along with the xf86-video-modesetting support, but within xf86-video-amdgpu Git and pending for xf86-video-ati is support for the TILE property in dealing with tiled displays...