Follow on to Namespace fixup for D68340

remove using directive that can make lookup ambiguous.

Author: daltenty

clang/lib/Driver/ToolChains/AIX.cpp

@@ -14,7 +14,6 @@
 #include "clang/Driver/SanitizerArgs.h"
 #include "llvm/Option/ArgList.h"
 
-namespace aix = clang::driver::tools::aix;
 using AIX = clang::driver::toolchains::AIX;
 using namespace clang::driver;
 using namespace clang::driver::tools;