[WebAssembly] Wrap definitions in namespace lld { namespace wasm {. NFC

Similar to D68323, but for wasm.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D68759

llvm-svn: 374279
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index b53ddaf..92069ea 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -21,10 +21,10 @@
 using namespace llvm;
 using namespace llvm::wasm;
 using namespace llvm::object;
-using namespace lld;
-using namespace lld::wasm;
 
-SymbolTable *lld::wasm::symtab;
+namespace lld {
+namespace wasm {
+SymbolTable *symtab;
 
 void SymbolTable::addFile(InputFile *file) {
   log("Processing: " + toString(file));
@@ -692,3 +692,6 @@
     }
   }
 }
+
+} // namespace wasm
+} // namespace lld