Work around for ios 64 bit build warning - use explicit word register for int.

BUG=430
TESTED=local ios 64 bit build
R=bcornell@google.com

Review URL: https://webrtc-codereview.appspot.com/47039004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1381 16f28f9a-4ce2-e073-06de-1de4eb20be90

source/row_neon64.cc

@@ -1387,7 +1387,7 @@ void ARGBToRGB565DitherRow_NEON(const uint8* src_argb, uint8* dst_rgb,
   "1:                                          \n"
     MEMACCESS(1)
     "ld4        {v20.8b,v21.8b,v22.8b,v23.8b}, [%1], #32 \n"  // load 8 pixels
-    "subs       %3, %3, #8                     \n"  // 8 processed per loop.
+    "subs       %w3, %w3, #8                   \n"  // 8 processed per loop.
     "uqadd      v20.8b, v20.8b, v1.8b          \n"
     "uqadd      v21.8b, v21.8b, v1.8b          \n"
     "uqadd      v22.8b, v22.8b, v1.8b          \n"