ACPI / Wakeup: Simplify enabling of wakeup devices

To simplify the enabling of wakeup devices during system suspend and
hibernation, merge acpi_enable_wakeup_device_prep() with
acpi_disable_wakeup_device() and remove unnecessary (and no longer
valid) comments from the latter.  Rename acpi_enable_wakeup_device()
to acpi_enable_wakeup_devices() and acpi_disable_wakeup_device()
to acpi_disable_wakeup_devices(), because these functions usually
operate on multiple device objects.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 8704ca78..93441c9 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -73,8 +73,7 @@
 #endif
 	printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
 		acpi_state);
-	acpi_enable_wakeup_device_prep(acpi_state);
-	acpi_enable_wakeup_device(acpi_state);
+	acpi_enable_wakeup_devices(acpi_state);
 	acpi_enter_sleep_state_prep(acpi_state);
 	return 0;
 }
@@ -153,7 +152,7 @@
 
 	printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
 		acpi_state);
-	acpi_disable_wakeup_device(acpi_state);
+	acpi_disable_wakeup_devices(acpi_state);
 	acpi_leave_sleep_state(acpi_state);
 
 	/* reset firmware waking vector */