Update opus from 1.1.4 to 1.2.1

code/opus-1.1.4/silk/decode_frame.c

@@ -97,6 +97,7 @@ opus_int silk_decode_frame(
         psDec->first_frame_after_reset = 0;
     } else {
         /* Handle packet loss by extrapolation */
+        psDec->indices.signalType = psDec->prevSignalType;
         silk_PLC( psDec, psDecCtrl, pOut, 1, arch );
     }