[WebAssembly] Remove unused methods from MCWasmObjectTargetWriter

These methods looks like they were originally came from
MCELFObjectTargetWriter but they are never called by the
WasmObjectWriter.

Remove these methods meant the declaration of WasmRelocationEntry
could also move into the cpp file.

Differential Revision: https://reviews.llvm.org/D33905

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304804 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCWasmObjectTargetWriter.cpp

@@ -17,11 +17,5 @@ using namespace llvm;
 MCWasmObjectTargetWriter::MCWasmObjectTargetWriter(bool Is64Bit_)
     : Is64Bit(Is64Bit_) {}
 
-bool MCWasmObjectTargetWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
-                                                       unsigned Type) const {
-  return false;
-}
-
-void MCWasmObjectTargetWriter::sortRelocs(
-    const MCAssembler &Asm, std::vector<WasmRelocationEntry> &Relocs) {
-}
+// Pin the vtable to this object file
+MCWasmObjectTargetWriter::~MCWasmObjectTargetWriter() = default;