set d19 alpha on inner loop

TBR=harryjin@google.com
BUG=libyuv:521

Review URL: https://codereview.chromium.org/1429263004 .

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1532
+Version: 1533
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1532
+#define LIBYUV_VERSION 1533
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/row_neon.cc

@@ -265,11 +265,11 @@ void I422ToRGBARow_NEON(const uint8* src_y,
                         int width) {
   asm volatile (
     YUVTORGB_SETUP
-    "vmov.u8    d19, #255                      \n"
   "1:                                          \n"
     READYUV422
     YUVTORGB
     "subs       %4, %4, #8                     \n"
+    "vmov.u8    d19, #255                      \n"  // d19 modified by YUVTORGB
     MEMACCESS(3)
     "vst4.8     {d19, d20, d21, d22}, [%3]!    \n"
     "bgt        1b                             \n"