Remove unneeded check for RESTORE_NONE

av1_loop_restoration_corners_in_sb, which is called before this,
will signal not to read the coefficients if RESTORE_NONE is set.

Change-Id: I6763c590506ddf6e4a0092c8cf9892bcc39eca60

av1/decoder/decodeframe.c

diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 19d3286..bf25048 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -1681,7 +1681,7 @@
     int runit_idx) {
   const RestorationInfo *rsi = &cm->rst_info[plane];
   RestorationUnitInfo *rui = &rsi->unit_info[runit_idx];
-  if (rsi->frame_restoration_type == RESTORE_NONE) return;
+  assert(rsi->frame_restoration_type != RESTORE_NONE);
 
   assert(!cm->features.all_lossless);