Cleaning up vp9_cx_iface.c.

Marking unused parameters with (void), adding consts, fixing formatting.

Change-Id: I8ac1e6606c0f2673f78bc41830e672a680ffed02
diff --git a/vpx/internal/vpx_codec_internal.h b/vpx/internal/vpx_codec_internal.h
index 51ca65e..83c3308 100644
--- a/vpx/internal/vpx_codec_internal.h
+++ b/vpx/internal/vpx_codec_internal.h
@@ -170,8 +170,8 @@
  * \ref MUST be non-zero.
  */
 typedef const struct vpx_codec_ctrl_fn_map {
-  int                    ctrl_id;
-  vpx_codec_control_fn_t   fn;
+  int ctrl_id;
+  vpx_codec_control_fn_t fn;
 } vpx_codec_ctrl_fn_map_t;
 
 /*!\brief decode data function pointer prototype