[CompilerRT] use .p2align, .balign instead of .align

The .align statements in ARM assembly routines is actually meant to be a power
of 2 alignment (e.g. .align 2 == 4 byte alignment, not 2).  Switch to using
.p2align.  .p2align is guaranteed to be a power-of-two alignment always and much
more explicit.

The .align in the case of x86_64 is byte alignment, use .balign instead of
.align.

llvm-svn: 208578
diff --git a/compiler-rt/lib/builtins/arm/sync_synchronize.S b/compiler-rt/lib/builtins/arm/sync_synchronize.S
index aa18f04..178f245 100644
--- a/compiler-rt/lib/builtins/arm/sync_synchronize.S
+++ b/compiler-rt/lib/builtins/arm/sync_synchronize.S
@@ -21,7 +21,7 @@
 
 #if __APPLE__
 
-	.align 2
+	.p2align 2
 DEFINE_COMPILERRT_PRIVATE_FUNCTION(__sync_synchronize)
 	stmfd	sp!, {r7, lr}
 	add		r7, sp, #0