Remove the unused HElementsKind instruction.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index da96eb24c9af151f22863d090891aa3ca8d6f4f9..ff6d4c4e932bc52c93ad97065184af6650b5d006 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -1651,20 +1651,6 @@ void LCodeGen::DoMapEnumLength(LMapEnumLength* instr) {
 }
 
 
-void LCodeGen::DoElementsKind(LElementsKind* instr) {
-  Register result = ToRegister(instr->result());
-  Register input = ToRegister(instr->value());
-
-  // Load map into |result|.
-  __ lw(result, FieldMemOperand(input, HeapObject::kMapOffset));
-  // Load the map's "bit field 2" into |result|. We only need the first byte,
-  // but the following bit field extraction takes care of that anyway.
-  __ lbu(result, FieldMemOperand(result, Map::kBitField2Offset));
-  // Retrieve elements_kind from bit field 2.
-  __ Ext(result, result, Map::kElementsKindShift, Map::kElementsKindBitCount);
-}
-
-
 void LCodeGen::DoValueOf(LValueOf* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());