tests/swscale: fix sscanf return value check

We only parse 12 values, so this check always failed. Regression caused by
a change to the print format.

Fixes: 59c39a79ca
Signed-off-by: Niklas Haas <git@haasn.dev>
Sponsored-by: Sovereign Tech Fund

libswscale/tests/swscale.c

@@ -309,7 +309,7 @@ static int run_file_tests(const AVFrame *ref, FILE *fp, struct options opts)
                      src_fmt_str, &sw, &sh, dst_fmt_str, &dw, &dh,
                      &mode.flags, &mode.dither,
                      &mse[0], &mse[1], &mse[2], &mse[3]);
-        if (ret != 13) {
+        if (ret != 12) {
             printf("%s", buf);
             continue;
         }