llvm-strings: remove default for -Wcovered-switch-default

Fix the -Werror build by removing the unnecessary default case in the
covered switch.  NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292708 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-strings/llvm-strings.cpp

@@ -57,7 +57,6 @@ static void strings(raw_ostream &OS, StringRef FileName, StringRef Contents) {
     if (PrintFileName)
       OS << FileName << ":";
     switch (Radix) {
-    default:
     case none:
       break;
     case octal: