mxfdec: fix NULL checking in mxf_get_sorted_table_segments()

The following out-of-memory check is broken.

    *sorted_segments  = av_mallocz(...);
    if (!sorted_segments) { ... }

The correct NULL check should use *sorted_segments.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavformat/mxfdec.c

@@ -955,7 +955,7 @@ static int mxf_get_sorted_table_segments(MXFContext *mxf, int *nb_sorted_segment
 
     *sorted_segments  = av_mallocz(nb_segments * sizeof(**sorted_segments));
     unsorted_segments = av_mallocz(nb_segments * sizeof(*unsorted_segments));
-    if (!sorted_segments || !unsorted_segments) {
+    if (!*sorted_segments || !unsorted_segments) {
         av_freep(sorted_segments);
         av_free(unsorted_segments);
         return AVERROR(ENOMEM);