avcodec/rscc: Fix constant

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/rscc.c

@@ -314,7 +314,7 @@ static int rscc_decode_frame(AVCodecContext *avctx, void *data,
         const uint8_t *pal = av_packet_get_side_data(avpkt,
                                                      AV_PKT_DATA_PALETTE,
                                                      &size);
-        if (pal && size == AV_PKT_DATA_PALETTE) {
+        if (pal && size == AVPALETTE_SIZE) {
             frame->palette_has_changed = 1;
             memcpy(ctx->pal, pal, AVPALETTE_SIZE);
         } else if (pal) {