Code refactoring: pull SchedPreference enum from TargetLowering.h to TargetMachine.h and put it in its own namespace.

llvm-svn: 104147
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index f5373cb..62852b1 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -466,7 +466,7 @@
   setTargetDAGCombine(ISD::MUL);
 
   setStackPointerRegisterToSaveRestore(ARM::SP);
-  setSchedulingPreference(SchedulingForRegPressure);
+  setSchedulingPreference(Sched::RegPressure);
 
   // FIXME: If-converter should use instruction latency to determine
   // profitability rather than relying on fixed limits.