Fix compile warnings on windows.

Change-Id: If74bc6110016bc75ea3883ab136fbbac88f6a913
diff --git a/vp8/encoder/onyx_if.c b/vp8/encoder/onyx_if.c
index 51b154f..73f6583 100644
--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -362,7 +362,7 @@
                                         VP8_CONFIG *oxcf,
                                         const int prev_num_layers)
 {
-    unsigned int i;
+    int i;
     double prev_layer_frame_rate = 0;
     const int curr_num_layers = cpi->oxcf.number_of_layers;
     // If the previous state was 1 layer, get current layer context from cpi.
diff --git a/vp9/common/vp9_findnearmv.h b/vp9/common/vp9_findnearmv.h
index 91736fe..17fef12 100644
--- a/vp9/common/vp9_findnearmv.h
+++ b/vp9/common/vp9_findnearmv.h
@@ -72,7 +72,7 @@
 
 vp9_prob *vp9_mv_ref_probs(VP9_COMMON *pc,
                            vp9_prob p[VP9_INTER_MODES - 1],
-                           const int context);
+                           int context);
 
 void vp9_append_sub8x8_mvs_for_idx(VP9_COMMON *pc,
                                    MACROBLOCKD *xd,