btrfs: add helpers for FS_XFLAG_* conversion

Preparatory work for the FS_IOC_FSGETXATTR ioctl, basic conversions and
checking helpers.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-03-26 19:42:05 +02:00
commit 19f93b3cd8