LU-13814 osc: remove "osc_page_transfer_add" wrapper

LU-13814 osc: remove "osc_page_transfer_add" wrapper

osc_page_transfer_add is just a wrapped around osc_lru_use,
let's remove it to be more explicit about what we're
actually doing.

Test-Parameters: trivial
Signed-off-by: Patrick Farrell <patrick.farrell@oracle.com>
Change-Id: I495a90bee7dc8f8c9d823fa47f9303d2fac2a829
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52086
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Qian Yingjin <qian@ddn.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>