common/rc: Introduce helpers for new dax mount options and FS_XFLAG_DAX

1) _check_scratch_dax_mountopt() checks old/new dax mount option and
   returns a value.
2) _require_scratch_dax_mountopt() throws notrun if _check_scratch_dax_mountopt()
   returns a non-zero value.
3) _require_dax_iflag() checks FS_XFLAG_DAX.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
1 file changed