nfsd : Define NFSD only when FILE_LOCKING is enabled

Enable NFSD only when FILE_LOCKING is enabled, since we don't want to
support NFSD without FILE_LOCKING.
Signed-off-by: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/Kconfig

 config NFSD
 	tristate "NFS server support"
 	depends on INET
+	depends on FILE_LOCKING
 	select LOCKD
 	select SUNRPC
 	select EXPORTFS