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/ac.c b/drivers/acpi/ac.c
index b53c2cf..26d7070 100644
--- a/drivers/acpi/ac.c
+++ b/drivers/acpi/ac.c
@@ -204,7 +204,7 @@
 	case ACPI_NOTIFY_BUS_CHECK:
 	case ACPI_NOTIFY_DEVICE_CHECK:
 		acpi_ac_get_state(ac);
-		acpi_bus_generate_event(device, event, (u32) ac->state);
+		acpi_bus_generate_proc_event(device, event, (u32) ac->state);
 		acpi_bus_generate_netlink_event(device->pnp.device_class,
 						  device->dev.bus_id, event,
 						  (u32) ac->state);