ACPI: Schedule /proc/acpi/event for removal

Schedule /proc/acpi/event for removal in 6 months.

Re-name acpi_bus_generate_event() to acpi_bus_generate_proc_event()
to make sure there is no confusion that it is for /proc/acpi/event only.

Add CONFIG_ACPI_PROC_EVENT to allow removal of /proc/acpi/event.
There is no functional change if CONFIG_ACPI_PROC_EVENT=y

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 9f0bf90..91dc4b3 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -867,7 +867,7 @@
 	case ACPI_NOTIFY_DEVICE_CHECK:
 		device = battery->device;
 		acpi_battery_notify_update(battery);
-		acpi_bus_generate_event(device, event,
+		acpi_bus_generate_proc_event(device, event,
 					acpi_battery_present(battery));
 		acpi_bus_generate_netlink_event(device->pnp.device_class,
 						  device->dev.bus_id, event,