Instead of having to include xenctrl.h for getting definitions of cpu
barriers, add a dedicated header for that purpose.
Switch the xen-9pfsd daemon to use the new header instead of xenctrl.h.
This is in preparation of making Xenstore independent from libxenctrl.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>