LU-18387 kernel: new kernel [RHEL 9.5 5.14.0-503.2.1.el9_5]

LU-18387 kernel: new kernel [RHEL 9.5 5.14.0-503.2.1.el9_5]

This patch makes changes to support new RHEL 9.5 release
for Lustre client.

Lustre-change: https://review.whamcloud.com/56748
Lustre-commit: TBD (from a347e8bece92e00af02d5499b092700954c4fb8e)

LU-17243 build: compatibility updates for kernel 6.6

linux kernel v5.19-rc1-4-gc4f135d64382
  workqueue: Wrap flush_workqueue() using a macro
linux kernel v6.5-rc1-7-g20bdedafd2f6
  workqueue: Warn attempt to flush system-wide workqueues.
If __flush_workqueue(system_wq) is not available fall back to
flush_scheduled_work()

Lustre-change: https://review.whamcloud.com/52908
Lustre-commit: a0e6d6f7327598d13661bb14098a9f21f2035285

LU-17592 build: compatibility updates for kernel 6.8

Linux commit v6.7-rc1-3-gda549bdd15c2
  dentry: switch the lists of children to hlist
Provide trival wrappers to abstract the changed members

Lustre-change: https://review.whamcloud.com/54229
Lustre-commit: 6d27c2c8c72e853a238fd3fc7f42d658188ca02f

Test-Parameters: trivial \
  mdtcount=4 mdscount=2 clientdistro=el9.5 testlist=sanity
Test-Parameters: optional clientdistro=el9.5 testgroup=full-part-1
Test-Parameters: optional clientdistro=el9.5 testgroup=full-part-2
Test-Parameters: optional clientdistro=el9.5 testgroup=full-part-3

Change-Id: I1bce12b2b7190bcbd880916049667630aba700c8
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56754
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>