Fix 100l incorrect bitmask check.

Originally committed as revision 20197 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dca.c

@@ -609,7 +609,7 @@ static int dca_subframe_header(DCAContext * s)
                 s->joint_scale_factor[j][k] = scale;    /*joint_scale_table[scale]; */
             }
 
-            if (!s->debug_flag & 0x02) {
+            if (!(s->debug_flag & 0x02)) {
                 av_log(s->avctx, AV_LOG_DEBUG,
                        "Joint stereo coding not supported\n");
                 s->debug_flag |= 0x02;