locks: clean up vfs_setlease kerneldoc comments

 * vfs_setlease        -       sets a lease on an open file

 * @filp: file pointer

 * @arg: type of lease to obtain

 *	@lease: file_lock to use

 *

 *	Call this to establish a lease on the file.

 *	The (*lease)->fl_lmops->lm_break operation must be set; if not,

 *	break_lease will oops!

 *

 *	This will call the filesystem's setlease file method, if

 *	defined.  Note that there is no getlease method; instead, the

 *	filesystem setlease method should call back to setlease() to

 *	add a lease to the inode's lease list, where fcntl_getlease() can

 *	find it.  Since fcntl_getlease() only reports whether the current

 *	task holds a lease, a cluster filesystem need only do this for

 *	leases held by processes on this node.

 *

 *	There is also no break_lease method; filesystems that

 *	handle their own leases should break leases themselves from the

 *	filesystem's open, create, and (on truncate) setattr methods.

 *

 *	Warning: the only current setlease methods exist only to disable

 *	leases in certain cases.  More vfs changes may be required to

 *	allow a full filesystem lease implementation.

 * @lease: file_lock to use when adding a lease

 *

 * Call this to establish a lease on the file. The "lease" argument is not

 * used for F_UNLCK requests and may be NULL. For commands that set or alter

 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;

 * if not, this function will return -ENOLCK (and generate a scary-looking

 * stack trace).

 */

int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)