LU-13814 osc: skip lru_add for transient pages

LU-13814 osc: skip lru_add for transient pages

Transient pages do not go in the LRU, so don't bother
trying to add them.

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I90e3cca2229e1ae7d769c0534b5b6e0be2357ad9
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52070
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>