Update x86-sse2.h

add stosb fill ssvb#16

Author: sfx2000

x86-sse2.h

@@ -36,7 +36,9 @@ void aligned_block_copy_movsb(int64_t * __restrict dst,
 void aligned_block_copy_movsd(int64_t * __restrict dst,
                               int64_t * __restrict src,
                               int                  size);
-
+void aligned_block_fill_stosb(int64_t * __restrict dst,
+                              int64_t * __restrict src,
+                              int                  size);
 void aligned_block_copy_sse2(int64_t * __restrict dst,
                              int64_t * __restrict src,
                              int                  size);