LU-16667 build: struct mnt_idmap, linux/filelock.h

LU-16667 build: struct mnt_idmap, linux/filelock.h

Linux commit v6.2-rc3-9-g5970e15dbcfe
  filelock: move file locking definitions to separate
            header file

Add configure test for linux/filelock.h and include it
where needed.

linux kernel v6.2-rc1-4-gb74d24f7a74f
  fs: port ->getattr() to pass mnt_idmap
linux kernel v6.2-rc1-3-gc1632a0f1120
  fs: port ->setattr() to pass mnt_idmap

Add a configure test for mnt_idmap and fallback to using
user_namespace for older kernels.

Lustre-change: https://review.whamcloud.com/50420
Lustre-commit: 3011aa564a8c682aafbc6071b9866e266d8a6232

Was-Change-Id: Ib8cbb3157fb11b4f1fc55f1626c2998cb202bd8c

LU-16667 build: kernel_cap_t contains u64

linux kernel v6.2-13111-gf122a08b197d
  capability: just use a 'u64' instead of a 'u32[2]' array

Add configure test for kernel_cap_t as u64 and provide
and accessor for the least significant 32 bits.

As of linux commit v3.6-10973-g607ca46e97a1 lustre implicitly
started to ignore some capabilities, see:
   include/uapi/linux/capability.h

The last capability flag was added by:
   linux commit v5.8-rc5-1-g124ea650d307

The capabilities the Lustre currently ignores are:
 - CAP_MAC_OVERRIDE
 - CAP_MAC_ADMIN
 - CAP_SYSLOG
 - CAP_WAKE_ALARM
 - CAP_BLOCK_SUSPEND
 - CAP_AUDIT_READ
 - CAP_PERFMON
 - CAP_BPF
 - CAP_CHECKPOINT_RESTORE

None of which appear to be important to Lustre operations
and should be fine to continue ignore.

Lustre-change: https://review.whamcloud.com/50421
Lustre-commit: ea9532fb731bbfe041010e2224219479c2c0d71b

Was-Change-Id: I48ad7b1a34fff378c260dc73ea91b22aaa0d7469

HPE-bug-id: LUS-11557
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: Ib8cbb3157fb11b4f1fc55f1626c2998cb202bd8c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59083
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Deiter <adeiter@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>