mISDN: remove unneeded mISDN_class_release()

The mISDN_class_release() is not needed at all, as the class structure
is static, and it does not actually do anything either, so it is safe to
remove as struct class does not require a release callback.

Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230329060127.2688492-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/isdn/mISDN/core.c

@@ -152,17 +152,11 @@ static int mISDN_uevent(const struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
-static void mISDN_class_release(struct class *cls)
-{
-	/* do nothing, it's static */
-}
-
 static struct class mISDN_class = {
 	.name = "mISDN",
 	.dev_uevent = mISDN_uevent,
 	.dev_groups = mISDN_groups,
 	.dev_release = mISDN_dev_release,
-	.class_release = mISDN_class_release,
 };
 
 static int