ART: mterp arm/arm64 cleanup

Assembly code cleanup in response to comments from already-submitted
CL: https://android-review.googlesource.com/#/c/188977/

Change-Id: I0ea85c5759a08cb50ef3e97dc5cf79b3ba041640
diff --git a/runtime/interpreter/mterp/arm64/header.S b/runtime/interpreter/mterp/arm64/header.S
index 7223750..7101ba9 100644
--- a/runtime/interpreter/mterp/arm64/header.S
+++ b/runtime/interpreter/mterp/arm64/header.S
@@ -272,7 +272,7 @@
  * Convert a virtual register index into an address.
  */
 .macro VREG_INDEX_TO_ADDR reg, vreg
-    add     \reg, xFP, \vreg, lsl #2   /* WARNING/FIXME: handle shadow frame vreg zero if store */
+    add     \reg, xFP, \vreg, lsl #2   /* WARNING: handle shadow frame vreg zero if store */
 .endm
 
 /*