[Xtensa] Use parseOptionalToken. NFC

Author: MaskRay

llvm/lib/Target/Xtensa/AsmParser/XtensaAsmParser.cpp

@@ -642,14 +642,12 @@ bool XtensaAsmParser::ParseInstructionWithSR(ParseInstructionInfo &Info,
     if (parseOperand(Operands, Name))
       return true;
 
-    if (!getLexer().is(AsmToken::Comma)) {
+    if (!parseOptionalToken(AsmToken::Comma)) {
       SMLoc Loc = getLexer().getLoc();
       getParser().eatToEndOfStatement();
       return Error(Loc, "unexpected token");
     }
 
-    getLexer().Lex();
-
     // Parse second operand
     if (parseOperand(Operands, Name, true))
       return true;
@@ -685,14 +683,9 @@ bool XtensaAsmParser::ParseInstruction(ParseInstructionInfo &Info,
     return true;
 
   // Parse until end of statement, consuming commas between operands
-  while (getLexer().is(AsmToken::Comma)) {
-    // Consume comma token
-    getLexer().Lex();
-
-    // Parse next operand
+  while (parseOptionalToken(AsmToken::Comma))
     if (parseOperand(Operands, Name))
       return true;
-  }
 
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     SMLoc Loc = getLexer().getLoc();