LU-16796 lnet: Change struct lmv_stripe_object to use kref

LU-16796 lnet: Change struct lmv_stripe_object to use kref

This patch changes struct lmv_stripe_object to use
kref instead of atomic_t

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I7df086a23f59eb352c0f07b96e30bfdf9bc96cad
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56363
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>