[CodeGen] Rename MachineInstrBuilder::addOperand. NFC

Rename from addOperand to just add, to match the other method that has been
added to MachineInstrBuilder for adding more than just 1 operand.

See https://reviews.llvm.org/D28057 for the whole discussion.

Differential Revision: https://reviews.llvm.org/D28556

llvm-svn: 291891
diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 01f91b9..ef766db 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -470,7 +470,7 @@
 
   // No need to fold return, the meta data, and function arguments
   for (unsigned i = 0; i < StartIdx; ++i)
-    MIB.addOperand(MI.getOperand(i));
+    MIB.add(MI.getOperand(i));
 
   for (unsigned i = StartIdx; i < MI.getNumOperands(); ++i) {
     MachineOperand &MO = MI.getOperand(i);
@@ -490,7 +490,7 @@
       MIB.addImm(SpillOffset);
     }
     else
-      MIB.addOperand(MO);
+      MIB.add(MO);
   }
   return NewMI;
 }