[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/Target/SystemZ/SystemZShortenInst.cpp b/llvm/lib/Target/SystemZ/SystemZShortenInst.cpp
index 83882fc..263aff8 100644
--- a/llvm/lib/Target/SystemZ/SystemZShortenInst.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZShortenInst.cpp
@@ -167,10 +167,10 @@
     MI.RemoveOperand(0);
     MI.setDesc(TII->get(Opcode));
     MachineInstrBuilder(*MI.getParent()->getParent(), &MI)
-      .addOperand(Dest)
-      .addOperand(Mode)
-      .addOperand(Src)
-      .addOperand(Suppress);
+        .add(Dest)
+        .add(Mode)
+        .add(Src)
+        .add(Suppress);
     return true;
   }
   return false;