MIPS64: Improve UInt32 to Double conversion.

src/crankshaft/mips64/lithium-codegen-mips64.cc

Index: src/crankshaft/mips64/lithium-codegen-mips64.cc
diff --git a/src/crankshaft/mips64/lithium-codegen-mips64.cc b/src/crankshaft/mips64/lithium-codegen-mips64.cc
index a615030fae84230b82bfd5f2b98fe6560b99b74e..ca809bd69512b2f1ae39918fe3a9070549c6b4dd 100644
--- a/src/crankshaft/mips64/lithium-codegen-mips64.cc
+++ b/src/crankshaft/mips64/lithium-codegen-mips64.cc
@@ -4736,7 +4736,7 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 
   FPURegister dbl_scratch = double_scratch0();
   __ mtc1(ToRegister(input), dbl_scratch);
-  __ Cvt_d_uw(ToDoubleRegister(output), dbl_scratch, f22);  // TODO(plind): f22?
+  __ Cvt_d_uw(ToDoubleRegister(output), dbl_scratch);
 }
 
 
@@ -4793,7 +4793,7 @@ void LCodeGen::DoDeferredNumberTagIU(LInstruction* instr,
     __ cvt_d_w(dbl_scratch, dbl_scratch);
   } else {
     __ mtc1(src, dbl_scratch);
-    __ Cvt_d_uw(dbl_scratch, dbl_scratch, f22);
+    __ Cvt_d_uw(dbl_scratch, dbl_scratch);
   }
 
   if (FLAG_inline_new) {