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 d3de14bf55d76c7fec6b9b3e0eaf7a6cfc10a1e5..c047083caf3f105535b72b75aaa82bf4ddcf2d62 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;
@@ -289,6 +290,7 @@ void InstructionSelector::VisitStore(Node* node) {
 #else
       case MachineRepresentation::kWord64:  // Fall through.
 #endif
+      case MachineRepresentation::kSimd128:  // Fall through.
       case MachineRepresentation::kNone:
         UNREACHABLE();
         return;
@@ -340,6 +342,7 @@ 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;
@@ -385,6 +388,7 @@ 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;