common/attr: add maximum acl count for f2fs

Add a max acl count into common/attr for f2fs in order to make f2fs passing generic/026 test case.

---
 common/attr | 3 +++
 1 file changed, 3 insertions(+)

index 86fe181..0efc26d 100644
@@ -42,6 +42,9 @@ _acl_get_max()
 	jfs)
 		echo 8191
 		;;
+	f2fs)
+		echo 506
+		;;
 	*)
 		echo 0
 		;;

2.7.0