denver: optimize memmove

Optimize 32-bit denver memmove with reversal memcpy.

Change-Id: Iaad0a9475248cdd7e4f50d58bea9db1b767abc88
diff --git a/libc/arch-arm/krait/krait.mk b/libc/arch-arm/krait/krait.mk
index 08342d6..631ab68 100644
--- a/libc/arch-arm/krait/krait.mk
+++ b/libc/arch-arm/krait/krait.mk
@@ -5,8 +5,9 @@
     arch-arm/krait/bionic/__strcat_chk.S \
     arch-arm/krait/bionic/__strcpy_chk.S \
 
-# Use cortex-a15 versions of strcat/strcpy/strlen.
+# Use cortex-a15 versions of strcat/strcpy/strlen and standard memmove
 libc_bionic_src_files_arm += \
     arch-arm/cortex-a15/bionic/strcat.S \
     arch-arm/cortex-a15/bionic/strcpy.S \
     arch-arm/cortex-a15/bionic/strlen.S \
+    bionic/memmove.c \