On old kernel, linux/fs.h doesn't include FS_IOC_FSGETXATTR and FS_IOC_FSGETXATTR
ioctl flag. It also doesn't include fsxattr struct. To fix this error, just
use global.h like fsstress.c.
Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Eryu Guan <guaneryu@gmail.com>