MIPS64: Fix InterpreterEntryTrampoline().

Was incorrectly loading BytecodeArray::kFrameSizeOffset as 64-bit int.

TEST=cctest/test-interpreter/TestInterpreterReturn
BUG=

Review URL: https://codereview.chromium.org/1286343002

Cr-Commit-Position: refs/heads/master@{#30159}

src/mips64/builtins-mips64.cc

@@ -904,8 +904,8 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
 
   // Allocate the local and temporary register file on the stack.
   {
-    // Load frame size from the BytecodeArray object.
-    __ ld(a4, FieldMemOperand(kInterpreterBytecodeArrayRegister,
+    // Load frame size (word) from the BytecodeArray object.
+    __ lw(a4, FieldMemOperand(kInterpreterBytecodeArrayRegister,
                               BytecodeArray::kFrameSizeOffset));
 
     // Do a stack check to ensure we don't go over the limit.