drm/radeon: wait for 3D idle before using CP DMA
drm/radeon: wait for 3D idle before using CP DMA

Make sure the 3D engine is idle before using CP DMA for
bo copies.

Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>
Cc: Marek Olšák <74bac9a67a04041c3586cda013cc5a11352e67be@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs