cifsd: remove unused including <linux/version.h>

Remove including <linux/version.h> that don't need it.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Zhiqi Song <songzhiqi1@huawei.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>