LU-13802 llite: trivial bio_dio switch check

LU-13802 llite: trivial bio_dio switch check

This adds a trivial version of the DIO BIO switch checking
function which doesn't ever switch.  This creates the basic
check function which we'll add to in future patches.

Test-Parameters: trivial
Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: Ia01df8d0f33246d3833c5327bcb1a07ac305492b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52586
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>