Common headers kernel client and server

[Steve French]

Looks like a good opportunity to move a few of the kernel headers used
by the kernel client (cifs.ko) and new kernel server (ksmbd.ko) into
common subdirectory ...

Some have diverged a lot, but others like "smbfsctl.h" would be fairly
easy to make common (and has value as well, as a few of the additions
made in the client version will help the server in the future and vice
versa).   In general, I lean toward having common headers for anything
defined in MS-SMB2, MS-FSCC, MS-SWN, MS-DTYP, MS-SMBD etc. and to try
to use the "official" names for fields and #defines so it is easy to
cross reference the code and the protocol documentation (even when
those field names in PDUs (protocol definitions) and infolevels etc.
use camelCase)

-- 
Thanks,

Steve