vp8/vp9: neon: msvc: move the 'ifdef _MSC_VER' bit to vpx_ports/mem.h.

                     fix compiling warning.

Change-Id: If8706a9046436f704c597e4275a6810c76ba7daa

vp8/common/arm/neon/sixtappredict_neon.c

@@ -9,10 +9,7 @@
  */
 
 #include <arm_neon.h>
-
-#ifdef _MSC_VER
-#define __builtin_prefetch(x)
-#endif
+#include "vpx_ports/mem.h"
 
 static const int8_t vp8_sub_pel_filters[8][8] = {
     {0,  0,  128,   0,   0, 0, 0, 0},  /* note that 1/8 pel positionyys are */

vp8/common/arm/neon/variance_neon.c

@@ -9,10 +9,7 @@
  */
 
 #include <arm_neon.h>
-
-#ifdef _MSC_VER
-#define __builtin_prefetch(x)
-#endif
+#include "vpx_ports/mem.h"
 
 unsigned int vp8_variance16x16_neon(
         const unsigned char *src_ptr,

vp8/common/arm/neon/vp8_subpixelvariance_neon.c

@@ -12,10 +12,6 @@
 #include "vpx_ports/mem.h"
 #include "vpx/vpx_integer.h"
 
-#ifdef _MSC_VER
-#define __builtin_prefetch(x)
-#endif
-
 static const uint16_t bilinear_taps_coeff[8][2] = {
     {128,   0},
     {112,  16},

vpx_ports/mem.h

@@ -23,7 +23,6 @@
 #warning No alignment directives known for this compiler.
 #define DECLARE_ALIGNED(n,typ,val)  typ val
 #endif
-#endif
 
 
 /* Declare an aligned array on the stack, for situations where the stack
@@ -44,4 +43,10 @@
 #define UNINITIALIZED_IS_SAFE(x) x=x
 #else
 #define UNINITIALIZED_IS_SAFE(x) x
+#endif
+
+#if HAVE_NEON && defined(_MSC_VER)
+#define __builtin_prefetch(x)
+#endif
+
 #endif  // VPX_PORTS_MEM_H_