schrodec: remove unnecessary check

The tag was dereferenced earier. From the libschroedinger code,
it's not obvious to see whether tag and frame would be NULL at
the same time. I think is likely that both will be non NULL
here, but that's not certain. Additional tests may be needed
to avoid dereferencing tag and/or frame, but what to do if
only one is NULL isn't obvious, as the _get_tag function does
transfer ownership so isn't undoable.

Coverity 1139850

ext/schroedinger/gstschrodec.c

@@ -498,8 +498,7 @@ gst_schro_dec_process (GstSchroDec * schro_dec, gboolean eos)
 
           schro_frame_unref (schro_frame);
         }
-        if (tag)
+        schro_tag_free (tag);
-          schro_tag_free (tag);
         if (!eos) {
           go = FALSE;
         }