Fix duplicate const.

Change-Id: I86be1f7421ed49d577cacf405f6e4b0daa85cfdc

vp9/common/vp9_loopfilter.c

diff --git a/vp9/common/vp9_loopfilter.c b/vp9/common/vp9_loopfilter.c
index f623c21..0aba719 100644
--- a/vp9/common/vp9_loopfilter.c
+++ b/vp9/common/vp9_loopfilter.c
@@ -285,7 +285,7 @@
 
     // Determine the vertical edges that need filtering
     for (c = 0; c < 64 / MI_SIZE && mi_col + c < cm->mi_cols; c += col_step) {
-      const MODE_INFO const *mi = xd->mode_info_context;
+      const MODE_INFO * const mi = xd->mode_info_context;
       const int skip_this = mi[c].mbmi.mb_skip_coeff
                             && mi[c].mbmi.ref_frame != INTRA_FRAME;
       // left edge of current unit is block/partition edge -> no skip