LU-9859 libcfs: move percpt_lock into lnet

LU-9859 libcfs: move percpt_lock into lnet

lnet is the only users of percpt_lock - and there are only two such
locks!
So move the code into lnet, as part of deprecating libcfs.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Id7091e88cf61228aa031921747fb9c7b08214931
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50832
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>