Refactor loading a pointer and loading an integer64 into a register instructions for X64

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index df0ac5d394796da80698a85ba7e1495ce0978c93..77552497057f1feffc9f21d8ec53d8c8df7f16c2 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -384,8 +384,7 @@ class MacroAssembler: public Assembler {
   void SafePush(Smi* src);
 
   void InitializeSmiConstantRegister() {
-    movq(kSmiConstantRegister,
-         reinterpret_cast<uint64_t>(Smi::FromInt(kSmiConstantRegisterValue)),
+    movq(kSmiConstantRegister, Smi::FromInt(kSmiConstantRegisterValue),
          RelocInfo::NONE64);
   }