xen / ACPI: notify xen when reduced hardware sleep is available

Use the acpi_os_prepare_extended_sleep() callback to notify xen
to make use of the reduced hardware sleep functionality

The xen hypervisor change underlying this is commit 62d1a69
("ACPI: support v5 (reduced HW) sleep interface") on the master
branch of git://xenbits.xen.org/xen.git.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Ben Guthro <benjamin.guthro@citrix.com>
Acked-by: Konrad Wilk <konrad.wilk@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/xen/acpi.h b/include/xen/acpi.h
index 46aa3d1..4ddd7dc 100644
--- a/include/xen/acpi.h
+++ b/include/xen/acpi.h
@@ -75,8 +75,10 @@
 	return -ENXIO;
 }
 
-int xen_acpi_notify_hypervisor_state(u8 sleep_state,
+int xen_acpi_notify_hypervisor_sleep(u8 sleep_state,
 				     u32 pm1a_cnt, u32 pm1b_cnd);
+int xen_acpi_notify_hypervisor_extended_sleep(u8 sleep_state,
+				     u32 val_a, u32 val_b);
 
 static inline int xen_acpi_suspend_lowlevel(void)
 {
@@ -93,7 +95,9 @@
 {
 	if (xen_initial_domain()) {
 		acpi_os_set_prepare_sleep(
-			&xen_acpi_notify_hypervisor_state);
+			&xen_acpi_notify_hypervisor_sleep);
+		acpi_os_set_prepare_extended_sleep(
+			&xen_acpi_notify_hypervisor_extended_sleep);
 
 		acpi_suspend_lowlevel = xen_acpi_suspend_lowlevel;
 	}