intel_primary_plane_{setplane,disable} were lacking struct_mutex locking
around their GEM operations.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reported-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>