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/Hexagon/HexagonTargetMachine.cpp b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
index 3a65418..cd05ece 100644
--- a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
@@ -138,7 +138,7 @@
 }
 
 TargetIRAnalysis HexagonTargetMachine::getTargetIRAnalysis() {
-  return TargetIRAnalysis([this](Function &F) {
+  return TargetIRAnalysis([this](const Function &F) {
     return TargetTransformInfo(HexagonTTIImpl(this, F));
   });
 }