avformat/aviobuf: Fix function pointer equality check

Broken in e8704a8f60
when ffurl_read() has been turned into a static inline function
different from the actually used function ffurl_read2().

Fixes ticket #10562.

Tested-by: Mitzsch01
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/aviobuf.c

@@ -1030,7 +1030,7 @@ URLContext* ffio_geturlcontext(AVIOContext *s)
     if (!s)
         return NULL;
 
-    if (s->opaque && s->read_packet == (int (*)(void *, uint8_t *, int))ffurl_read)
+    if (s->opaque && s->read_packet == ffurl_read2)
         return s->opaque;
     else
         return NULL;