fio: support modulus for the arithmetic parser

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/exp/expression-parser.l b/exp/expression-parser.l
index a0c6b24..bb80553 100644
--- a/exp/expression-parser.l
+++ b/exp/expression-parser.l
@@ -158,7 +158,7 @@
 		}
 	}
 \n	return 0;
-[+-/*()^]	return yytext[0];
+[+-/*()^%]	return yytext[0];
 
 .	{
 		yylval.v.has_error = 1;