avcodec/scpr: fix checking ret value of decode_run_i

Fixes Coverity CID 1441460.
Signed-off-by: Marton Balint <cus@passwd.hu>

libavcodec/scpr.c

@@ -359,7 +359,7 @@ static int decompress_i(AVCodecContext *avctx, uint32_t *dst, int linesize)
         ret = decode_run_i(avctx, ptype, run, &x, &y, clr,
                            dst, linesize, &lx, &ly,
                            backstep, off, &cx, &cx1);
-        if (run < 0)
+        if (ret < 0)
             return ret;
     }