LU-16612 llite: protect cp_state with vmpage lock

LU-16612 llite: protect cp_state with vmpage lock

cl_page_make_ready() calls cl_page_io_start() without vmpage lock
protection, and that could mess up cl_page's cp_state/cp_owner.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: Id0df7e14246aa561494a9b6e581cebc55241c4b9
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50180
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>