rtc: Replace memset() with av1_zero() in nonrd_pickmode.c

Simplify code using av1_zero() instead of memset() at appropriate
places in nonrd_pickmode.c

Change-Id: If3bb55016ff839de517bf6d07d44896b1e06ba19
diff --git a/av1/encoder/nonrd_pickmode.c b/av1/encoder/nonrd_pickmode.c
index 9737ba1..3cea363 100644
--- a/av1/encoder/nonrd_pickmode.c
+++ b/av1/encoder/nonrd_pickmode.c
@@ -400,9 +400,9 @@
   bp->best_pred = NULL;
   bp->best_motion_mode = SIMPLE_TRANSLATION;
   bp->num_proj_ref = 0;
-  memset(&bp->wm_params, 0, sizeof(bp->wm_params));
-  memset(&bp->blk_skip, 0, sizeof(bp->blk_skip));
-  memset(&bp->pmi, 0, sizeof(bp->pmi));
+  av1_zero(bp->wm_params);
+  av1_zero(bp->blk_skip);
+  av1_zero(bp->pmi);
 }
 
 static INLINE int subpel_select(AV1_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bsize,
@@ -3435,7 +3435,7 @@
   estimate_single_ref_frame_costs(cm, xd, mode_costs, segment_id, bsize,
                                   search_state->ref_costs_single);
 
-  memset(&search_state->mode_checked[0][0], 0, MB_MODE_COUNT * REF_FRAMES);
+  av1_zero(search_state->mode_checked);
 
   txfm_info->skip_txfm = 0;