Remove unused function vpx_de_mblock

vpx_config.h was not included so CONFIG_POSTPROC was never defined.

Change-Id: I777de499823afa286734549a8e7f4a93e7ad97f3

vpx_dsp/deblock.c

@@ -190,13 +190,3 @@ void vpx_mbpost_proc_down_c(unsigned char *dst, int pitch, int rows, int cols,
     }
   }
 }
-
-#if CONFIG_POSTPROC
-static void vpx_de_mblock(YV12_BUFFER_CONFIG *post, int q) {
-  vpx_mbpost_proc_across_ip(post->y_buffer, post->y_stride, post->y_height,
-                            post->y_width, q2mbl(q));
-  vpx_mbpost_proc_down(post->y_buffer, post->y_stride, post->y_height,
-                       post->y_width, q2mbl(q));
-}
-
-#endif