Fix compile error with --enable-postproc-visualizer

Typo.

Change-Id: I9cc6a4587c3d93c9f0da5e101d376741fc9622a4

vp8/common/postproc.c

@@ -806,7 +806,7 @@ int vp8_post_proc_frame(VP8_COMMON *oci, YV12_BUFFER_CONFIG *dest, vp8_ppflags_t
                 char zz[4];
                 int dc_diff = !(mi[mb_index].mbmi.mode != B_PRED &&
                               mi[mb_index].mbmi.mode != SPLITMV &&
-                              mi[mb_index].mbmi.mb_skip_coeff));
+                              mi[mb_index].mbmi.mb_skip_coeff);
 
                 if (oci->frame_type == KEY_FRAME)
                     sprintf(zz, "a");