ARM: Add optimization for constant RHS in DoMulI (try 2)

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
===================================================================
--- src/arm/macro-assembler-arm.cc	(revision 7433)
+++ src/arm/macro-assembler-arm.cc	(working copy)
@@ -294,7 +294,8 @@
              !src2.must_use_constant_pool() &&
              Isolate::Current()->cpu_features()->IsSupported(ARMv7) &&
              IsPowerOf2(src2.immediate() + 1)) {
-    ubfx(dst, src1, 0, WhichPowerOf2(src2.immediate() + 1), cond);
+    ubfx(dst, src1, 0,
+        WhichPowerOf2(static_cast<uint32_t>(src2.immediate()) + 1), cond);
 
   } else {
     and_(dst, src1, src2, LeaveCC, cond);