Replace a pre-UAL instruction with its modern form.

See the notes in the Chromium bug, and http://llvm.org/20427

BUG=chromium:124610,skia:900
R=djsollen@google.com, mtklein@google.com

Author: thakis@chromium.org

Review URL: https://codereview.chromium.org/455903002
diff --git a/src/opts/memset16_neon.S b/src/opts/memset16_neon.S
index b1719fa..7473a40 100644
--- a/src/opts/memset16_neon.S
+++ b/src/opts/memset16_neon.S
@@ -15,6 +15,8 @@
 
 ***************************************************************************/
 
+        .syntax unified
+
         .code 32
         .fpu neon
         .align 4
@@ -70,7 +72,7 @@
         strcs           r1, [r0], #4
         strcs           r1, [r0], #4
         lsls            r12, r12, #2
-        strcsh          r1, [r0], #2
+        strhcs          r1, [r0], #2
 memset_route:
         /*
          * Decide where to route for the maximum copy sizes.  Note that we