xfs: add static size checks for ioctl UABI

xfs: add static size checks for ioctl UABI

The ioctl structures in libxfs/xfs_fs.h are missing static size checks.
It is useful to have static size checks for these structures as adding
new fields to them could cause issues (e.g. extra padding that may be
inserted by the compiler). So add these checks to xfs/xfs_ondisk.h.

Due to different padding/alignment requirements across different
architectures, to avoid build failures, some structures are ommited from
the size checks. For example, structures with "compat_" definitions in
xfs/xfs_ioctl32.h are ommited.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>