cifs: Simplify SMB2 and SMB311 dependencies

cifs: Simplify SMB2 and SMB311 dependencies

BugLink: http://bugs.launchpad.net/bugs/1670508
* CIFS_SMB2 depends on CIFS, which depends on INET and selects NLS. So
  these dependencies do not need to be repeated for CIFS_SMB2.
* CIFS_SMB311 depends on CIFS_SMB2, which depends on INET. So this
  dependency doesn't need to be repeated for CIFS_SMB311.

Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Steve French <sfrench@samba.org>
(cherry picked from commit c1ecea87471bbb614f8121e00e5787f363140365)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>