st/vdpau: fix a small memory leak

The matrix filter wasn't freed on mixer destruction.

Signed-off-by: Christian König <deathsimple@vodafone.de>

src/gallium/state_trackers/vdpau/mixer.c

@@ -178,6 +178,11 @@ vlVdpVideoMixerDestroy(VdpVideoMixer mixer)
       FREE(vmixer->noise_reduction.filter);
    }
 
+   if (vmixer->sharpness.filter) {
+      vl_matrix_filter_cleanup(vmixer->sharpness.filter);
+      FREE(vmixer->sharpness.filter);
+   }
+
    FREE(vmixer);
 
    return VDP_STATUS_OK;