nfsd: clean up comments over nfs4_file definition

/*

 * nfs4_file: a file opened by some number of (open) nfs4_stateowners.

 *

 * These objects are global. nfsd only keeps one instance of a nfs4_file per

 * inode (though it may keep multiple file descriptors open per inode). These

 * are tracked in the file_hashtbl which is protected by the state_lock

 * spinlock.

 * These objects are global. nfsd keeps one instance of a nfs4_file per

 * filehandle (though it may keep multiple file descriptors for each). Each

 * inode can have multiple filehandles associated with it, so there is

 * (potentially) a many to one relationship between this struct and struct

 * inode.

 *

 * These are hashed by filehandle in the file_hashtbl, which is protected by

 * the global state_lock spinlock.

 */

struct nfs4_file {

	atomic_t		fi_ref;

	spinlock_t		fi_lock;

	struct hlist_node       fi_hash;    /* hash by "struct inode *" */

	struct hlist_node       fi_hash;	/* hash on fi_fhandle */

	struct list_head        fi_stateids;

	struct list_head	fi_delegations;

	/* One each for O_RDONLY, O_WRONLY, O_RDWR: */