drm/amdgpu: Don't crash system if we can't get crtc

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Harry Wentland 2015-11-25 15:42:09 -05:00 • committed by Alex Deucher
commit 9ddf940f5d