LU-6142 utils: use list_first/list_entry() on list heads

LU-6142 utils: use list_first/list_entry() on list heads

This patch changes
   list_entry(foo.next, ...)
to
   list_first_entry(&foo, ...)
and
   list_entry(foo.prev, ...)
to
   list_last_entry(&foo, ...)

in cases where 'foo' is a list head - not a list member.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I9daaaed044af596f6407801259cfb672150bfc34
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50830
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>