ARM rot_imm printing adjustment.

Allow the rot_imm operand to be optional. This sets the stage for refactoring
away the "rr" versions from the multiclasses and replacing them with Pat<>s.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136154 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp

@@ -841,7 +841,7 @@ void ARMInstPrinter::printRotImmOperand(const MCInst *MI, unsigned OpNum,
   unsigned Imm = MI->getOperand(OpNum).getImm();
   if (Imm == 0)
     return;
-  O << "ror #";
+  O << ", ror #";
   switch (Imm) {
   default: assert (0 && "illegal ror immediate!");
   case 1: O << "8\n"; break;