Syntax support of character in create table statement

[jackysp]

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

create table t (c1 NATIONAL CHARACTER(10));

2. What did you expect to see?
   Table created.

3. What did you see instead?
   ERROR 1105 (HY000): line 1 column 39 near "(10))" (total length 44)

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?
   8762592