yv12extend: make memcpy_short_addr static

Change-Id: I58612bd04fad6144722569d3db2899ba0fb947a6

vpx_scale/generic/yv12extend.c

diff --git a/vpx_scale/generic/yv12extend.c b/vpx_scale/generic/yv12extend.c
index 670144b..3eba563 100644
--- a/vpx_scale/generic/yv12extend.c
+++ b/vpx_scale/generic/yv12extend.c
@@ -211,7 +211,7 @@
 }
 
 #if CONFIG_VP9_HIGHBITDEPTH
-void memcpy_short_addr(uint8_t *dst8, const uint8_t *src8, int num) {
+static void memcpy_short_addr(uint8_t *dst8, const uint8_t *src8, int num) {
   uint16_t *dst = CONVERT_TO_SHORTPTR(dst8);
   uint16_t *src = CONVERT_TO_SHORTPTR(src8);
   memcpy(dst, src, num * sizeof(uint16_t));