constify the Function parameter to the TTI creation callback and
propagate to all callers/users/etc.

llvm-svn: 247864
diff --git a/llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp b/llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp
index d011c2b..efa3f82 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp
@@ -165,7 +165,7 @@
 }
 
 TargetIRAnalysis SystemZTargetMachine::getTargetIRAnalysis() {
-  return TargetIRAnalysis([this](Function &F) {
+  return TargetIRAnalysis([this](const Function &F) {
     return TargetTransformInfo(SystemZTTIImpl(this, F));
   });
 }