Replace int with uint32_t for non-negative values

This also fix a few compiler warnings of comparison between signed
and unsigned values.

Change-Id: I1d633f4dfdffff73743dc3f373564056c6d58813

av1/common/mvref_common.h

diff --git a/av1/common/mvref_common.h b/av1/common/mvref_common.h
index 80013e6..95fd6ca 100644
--- a/av1/common/mvref_common.h
+++ b/av1/common/mvref_common.h
@@ -276,7 +276,7 @@
                                       int search_col, int block_idx) {
 #if CONFIG_REF_MV
   (void)search_col;
-  (void)block_idx;  
+  (void)block_idx;
   return candidate->mbmi.mv[which_mv];
 #else
   return block_idx >= 0 && candidate->mbmi.sb_type < BLOCK_8X8

test/scan_test.cc

diff --git a/test/scan_test.cc b/test/scan_test.cc
index 22a6d85..ec2219c 100644
--- a/test/scan_test.cc
+++ b/test/scan_test.cc
@@ -23,15 +23,15 @@
   av1_augment_prob(prob, tx1d_size, tx1d_size);
   for (int r = 0; r < tx1d_size; ++r) {
     for (int c = 0; c < tx1d_size; ++c) {
-      const int idx = r * tx1d_size + c;
+      const uint32_t idx = r * tx1d_size + c;
       EXPECT_EQ(ref_prob[idx], prob[idx] >> 16);
     }
   }
 
-  const int mask = (1 << 10) - 1;
+  const uint32_t mask = (1 << 10) - 1;
   for (int r = 0; r < tx1d_size; ++r) {
     for (int c = 0; c < tx1d_size; ++c) {
-      const int idx = r * tx1d_size + c;
+      const uint32_t idx = r * tx1d_size + c;
       EXPECT_EQ(idx, mask ^ (prob[r * tx1d_size + c] & mask));
     }
   }