Arm32 dynamic function dispatch

Previous change was reverted in 9690b121e342676453c58f5940964350762085a0.
This change added .arch directive to kryo/ to avoid invalid instruction error.

Test: Run bionic unit test.
Test: Use gdb to make sure the right function is selected.
Test: Build previously failed target: make PRODUCT-sdk_phone_arm64-sdk
Change-Id: I14de41851121fc1a0b38c98fda5eb844b6a9695c
diff --git a/libc/arch-arm/kryo/bionic/memcpy.S b/libc/arch-arm/kryo/bionic/memcpy.S
index 74036ef..250f7bc 100644
--- a/libc/arch-arm/kryo/bionic/memcpy.S
+++ b/libc/arch-arm/kryo/bionic/memcpy.S
@@ -33,8 +33,14 @@
 #define PLDOFFS (16)
 #define PLDSIZE (128) /* L2 cache line size */
 
+        .syntax unified
+
+        // To avoid warning about deprecated instructions, add an explicit
+        // arch. The code generated is exactly the same.
+        .arch armv7-a
+
         .code 32
-ENTRY(__memcpy)
+ENTRY(__memcpy_kryo)
         push            {r0}
         .cfi_def_cfa_offset 4
         .cfi_rel_offset r0, 0
@@ -123,4 +129,4 @@
         pop             {r0}
         bx              lr
 
-END(__memcpy)
+END(__memcpy_kryo)