[C++11] Replace llvm::next and llvm::prior with std::next and std::prev.

Remove the old functions.

llvm-svn: 202636
diff --git a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
index 5efe1ff..36069ac 100644
--- a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -130,7 +130,7 @@
           MachineRegisterInfo::use_iterator nextI;
           for (MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg),
                E = MRI->use_end(); I!=E; I=nextI) {
-            nextI = llvm::next(I);  // I is invalidated by the setReg
+            nextI = std::next(I);  // I is invalidated by the setReg
             MachineOperand& Use = I.getOperand();
             MachineInstr *UseMI = Use.getParent();
             if (UseMI==MI)