platform/surface: aggregator: Make to_ssam_device_driver() respect constness

Make to_ssam_device_driver() a bit safer by replacing container_of()
with container_of_const() to respect the constness of the passed in
pointer, instead of silently discarding any const specifications. This
change also makes it more similar to to_ssam_device(), which already
uses container_of_const().

Signed-off-by: Maximilian Luz <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Hans de Goede <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>

include/linux/surface_aggregator/device.h

···
  * Return: Returns the pointer to the &struct ssam_device_driver wrapping the
  * given device driver @d.
  */
-static inline
-struct ssam_device_driver *to_ssam_device_driver(struct device_driver *d)
-{
-	return container_of(d, struct ssam_device_driver, driver);
-}
+#define to_ssam_device_driver(d)	container_of_const(d, struct ssam_device_driver, driver)
 
 const struct ssam_device_id *ssam_device_id_match(const struct ssam_device_id *table,
 						  const struct ssam_device_uid uid);