counter: constify the struct device_type usage

Since commit aed65af1 ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
counter_device_type variable to be a constant structure as well, placing it
into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240219-device_cleanup-counter-v1-1-24d0316ae815@marliere.net


Signed-off-by: William Breathitt Gray <william.gray@linaro.org>

drivers/counter/counter-core.c

@@ -49,7 +49,7 @@ static void counter_device_release(struct device *dev)
 	kfree(container_of(counter, struct counter_device_allochelper, counter));
 }
 
-static struct device_type counter_device_type = {
+static const struct device_type counter_device_type = {
 	.name = "counter_device",
 	.release = counter_device_release,
 };