LU-16363 build: fiemap flexible array

LU-16363 build: fiemap flexible array

Linux commit v5.19-rc2-1-g94dfc73e7cf4
 treewide: uapi: Replace zero-length arrays with flexible-array
 members
Adjust wiretest to handle flexible array when
sizeof(fiemap->fm_extents) is undefined.

Lustre-change: https://review.whamcloud.com/49305
Lustre-commit: fedf1e8bd70ccb2aaa64cb90111a7298d9bb2bf7

Test-Parameters: trivial
HPE-bug-id: LUS-11388
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: Ia2692d126a871b43e9144e5d151215166604702d
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/50216
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>