[NFC][CodeGen] Remove unused HasFakeUses MachineFunctionProperty

A previous commit d826b0c accidentally added a new MachineFunctionProperty,
HasFakeUses, that was unused by the commit (and results in an
uncovered-switch warning, which was fixed by a separate followup 1811e87);
this patch removes that enum value.

Author: SLTozer

llvm/include/llvm/CodeGen/MachineFunction.h

@@ -187,7 +187,6 @@ class MachineFunctionProperties {
     TiedOpsRewritten,
     FailsVerification,
     TracksDebugUserValues,
-    HasFakeUses,
     LastProperty = TracksDebugUserValues,
   };
 

llvm/lib/CodeGen/MachineFunction.cpp

@@ -94,7 +94,6 @@ static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
   // clang-format off
   switch(Prop) {
   case P::FailedISel: return "FailedISel";
-  case P::HasFakeUses: return "HasFakeUses";
   case P::IsSSA: return "IsSSA";
   case P::Legalized: return "Legalized";
   case P::NoPHIs: return "NoPHIs";