Add a kSimd128 machine type for Turbofan.

src/compiler/ppc/instruction-selector-ppc.cc

Index: src/compiler/ppc/instruction-selector-ppc.cc
diff --git a/src/compiler/ppc/instruction-selector-ppc.cc b/src/compiler/ppc/instruction-selector-ppc.cc
index e5655d14cd576802c1f9a726afead13ce1f7aad7..244e6f44c5b4b61cdfae198186128c5d70ae2bb7 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -200,6 +200,7 @@ void InstructionSelector::VisitLoad(Node* node) {
 #else
     case MachineRepresentation::kWord64:  // Fall through.
 #endif
+    case MachineRepresentation::kSimd128:  // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
@@ -302,6 +303,7 @@ void InstructionSelector::VisitStore(Node* node) {
 #else
       case MachineRepresentation::kWord64:  // Fall through.
 #endif
+      case MachineRepresentation::kSimd128:  // Fall through.
       case MachineRepresentation::kNone:
         UNREACHABLE();
         return;
@@ -353,6 +355,7 @@ void InstructionSelector::VisitCheckedLoad(Node* node) {
 #if !V8_TARGET_ARCH_PPC64
     case MachineRepresentation::kWord64:  // Fall through.
 #endif
+    case MachineRepresentation::kSimd128:  // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
@@ -398,6 +401,7 @@ void InstructionSelector::VisitCheckedStore(Node* node) {
 #if !V8_TARGET_ARCH_PPC64
     case MachineRepresentation::kWord64:  // Fall through.
 #endif
+    case MachineRepresentation::kSimd128:  // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
       return;