[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/MSP430/MSP430BranchSelector.cpp b/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
index 5fd6b63..424b5ae 100644
--- a/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
+++ b/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
@@ -194,8 +194,8 @@
         // Jump over the long branch on the opposite condition
         TII->reverseBranchCondition(Cond);
         MI = BuildMI(*MBB, MI, dl, TII->get(MSP430::JCC))
-                             .addMBB(NextMBB)
-                             .addOperand(Cond[0]);
+                 .addMBB(NextMBB)
+                 .add(Cond[0]);
         InstrSizeDiff += TII->getInstSizeInBytes(*MI);
         ++MI;
       }