avfilter/vf_uspp: assert that the qp_type is valid

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/vf_uspp.c

@@ -187,6 +187,7 @@ static inline int norm_qscale(int qscale, int type)
     case FF_QSCALE_TYPE_MPEG2: return qscale >> 1;
     case FF_QSCALE_TYPE_H264:  return qscale >> 2;
     case FF_QSCALE_TYPE_VP56:  return (63 - qscale + 2) >> 2;
+    default: av_assert0(0);
     }
     return qscale;
 }