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

commit 0573a1e2ea7e35bff08944a40f1adf2bb35cea61 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 c6b86421f1f9ddf9d706f2453159813ee39d0cf9)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>