drm/amdgpu: expand sienna chichlid reg access  support

Added dedicated 64bit reg read/write support

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed