staging: lustre: ldlm: remove unused 'work_list' arg from ldlm_process_flock_lock()

'work_list' is only set to NULL, and is never used.
So discard it.

Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>