PPC: [wasm-simd] Move bitmask into SIMD MVP

Port 6da647f

Original Commit Message:

    Now that 86 has branched, we can move bitmask into the SIMD MVP, it will
    not affect the current OT. (We want any OT extension to include
    bitmask.)

    Bitmask was accepted into the proposal in
    WebAssembly/simd#201.

R=zhin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I7518e1e8d7513a6931ff026eb3089fa896a6b587
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2379227
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#69587}

Author: Milad Farazmand

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

@@ -2402,6 +2402,12 @@ void InstructionSelector::VisitS128Const(Node* node) { UNIMPLEMENTED(); }
 
 void InstructionSelector::VisitS128AndNot(Node* node) { UNIMPLEMENTED(); }
 
+void InstructionSelector::VisitI8x16BitMask(Node* node) { UNIMPLEMENTED(); }
+
+void InstructionSelector::VisitI16x8BitMask(Node* node) { UNIMPLEMENTED(); }
+
+void InstructionSelector::VisitI32x4BitMask(Node* node) { UNIMPLEMENTED(); }
+
 void InstructionSelector::EmitPrepareResults(
     ZoneVector<PushParameter>* results, const CallDescriptor* call_descriptor,
     Node* node) {