cifs: delete duplicated words in header files

Drop repeated words in multiple comments.
(be, use, the, See)

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Steve French <sfrench@samba.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Steve French <stfrench@microsoft.com>