LU-16954 llite: add SB_I_CGROUPWB on super block for cgroup

LU-16954 llite: add SB_I_CGROUPWB on super block for cgroup

Cgroup support can be enabled per super_block by setting
SB_I_CGROUPWB in ->s_iflags.
Cgroup writeback requires support from both the bdi and
filesystem.
This patch adds SB_I_CGROUPWB flag on super block for Lustre.
This is required by the subsequent patch series to support
cgroup in Lustre.

Adding this flags for Lustre super block will cause the remount
failure on Maloo testing on Unbutu 2204 v5.15 kernel due to the
duplicate filename (sysfs) for bdi device.
To avoid remount failure, we explicitly unregister the sysfs for
the @bdi.

Lustre-change: https://review.whamcloud.com/51955
Lustre-commit: dcc1dd39a67f15de9174e7acdda599e3c54c1421

Test-Parameters: clientdistro=ubuntu2204 testlist=sanity-sec
Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: I7fff4f26aa1bfdb0e5de0c4bdbff44ed74d18c2d
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52538
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>