Remove extraneous qualifiers due to "using namespace". NFC

llvm-svn: 239038
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 88c76ea..059f424 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2185,6 +2185,6 @@
   return std::make_pair(IncludedFlagsBitmask, ExcludedFlagsBitmask);
 }
 
-bool clang::driver::isOptimizationLevelFast(const llvm::opt::ArgList &Args) {
+bool clang::driver::isOptimizationLevelFast(const ArgList &Args) {
   return Args.hasFlag(options::OPT_Ofast, options::OPT_O_Group, false);
 }