MipsISelLowering.cpp: Fix a warning, take two. [-Wunused-variable]

...and fix a typo, s/#ifdef/#ifndef/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173324 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index c01e852..5399b45 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -2891,10 +2891,10 @@
 const char* MipsTargetLowering::
   getMips16HelperFunction
     (Type* RetTy, ArgListTy &Args, bool &needHelper) const {
-  const unsigned int maxStubNum = 10;
   const unsigned int stubNum = getMips16HelperFunctionStubNumber(Args);
+#ifndef NDEBUG
+  const unsigned int maxStubNum = 10;
   assert(stubNum <= maxStubNum);
-#ifdef NDEBUG
   const bool validStubNum[maxStubNum+1] =
     {true, true, true, false, false, true, true, false, false, true, true};
   assert(validStubNum[stubNum]);