ncpfs: Support interacting with multiple user namespaces

ncpfs does not natively support uids and gids so this conversion was
simply a matter of updating the the type of the mounteduid, the uid
and the gid on the superblock. Fixing the ioctls that read them,
updating the mount option parser and the mount option printer.

Cc: Petr Vandrovec <petr@vandrovec.name>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

init/Kconfig

@@ -1072,7 +1072,6 @@ config UIDGID_CONVERTED
 
 	# Filesystems
 	depends on CIFS = n
-	depends on NCP_FS = n
 	depends on NFSD = n
 	depends on NFS_FS = n
 	depends on XFS_FS = n