MachineRegisterInfo: Remove unused arg from isConstantPhysReg(); NFC

llvm-svn: 285423
diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 4fdb6c5..265b4bfa 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -884,7 +884,7 @@
         // If the physreg has no defs anywhere, it's just an ambient register
         // and we can freely move its uses. Alternatively, if it's allocatable,
         // it could get allocated to something with a def during allocation.
-        if (!MRI.isConstantPhysReg(Reg, MF))
+        if (!MRI.isConstantPhysReg(Reg))
           return false;
       } else {
         // A physreg def. We can't remat it.