checkpatch: add more strict checking for block comments

This patch try to uniform the block comments, which gives more
consistent view to code reviewer.

 A:
    /* foo
     * bar */
 B:
    /*
     * foo
     * bar */
 C:
    /*
     * one-liner
     */
 D:
    /* one-liner
     */
 E:
    /* foo
     * bar
     * baz
     */
 A, B, C, D, E is not preferred

   /*
    * This block comments style
    * is preferred
    */

Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
use preferred block comments style

Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>