drm/amdgpu: Actually check flags for all context ops.

commit 0573a1e2 upstream.

Missing validation ...

Checked libdrm and it clears all the structs, so we should be
safe to just check everything.

Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit c6b86421)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>