cifs: Remove duplicated include in cifsglob.h

./fs/cifs/cifsglob.h: linux/scatterlist.h is included more than once.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3459
Fixes: f7f291e1

 ("cifs: fix oops during encryption")
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steve French <stfrench@microsoft.com>