greybus: endo: fix endo-id allocation flag

Use GFP_KERNEL for endo ida allocation in gb_endo_register, which is not
called from atomic context.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/staging/greybus/endo.c

@@ -439,7 +439,7 @@ static int gb_endo_register(struct greybus_host_device *hd,
 {
 	int retval;
 
-	retval = ida_simple_get(&greybus_endo_id_map, 0, 0, GFP_ATOMIC);
+	retval = ida_simple_get(&greybus_endo_id_map, 0, 0, GFP_KERNEL);
 	if (retval < 0)
 		return retval;