Revert "net: devlink: add RNLT lock assertion to devlink_compat_switch_id_get()"

This reverts commit 6005a8ae.

The assertion was intentionally removed in commit 043b8413 ("net:
devlink: remove redundant rtnl lock assert") and, contrary what is
described in the commit message, the comment reflects that: "Caller must
hold RTNL mutex or reference to dev...".
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Tested-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20220829121324.3980376-1-vladbu@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/devlink.c

@@ -12437,8 +12437,6 @@ int devlink_compat_switch_id_get(struct net_device *dev,
 	 * devlink_port instance cannot disappear in the middle. No need to take
 	 * any devlink lock as only permanent values are accessed.
 	 */
-	ASSERT_RTNL();
-
 	devlink_port = netdev_to_devlink_port(dev);
 	if (!devlink_port || !devlink_port->switch_port)
 		return -EOPNOTSUPP;