net: mdiobus: get rid of a BUG_ON()

stable inclusion
from stable-v5.10.44
commit be23c4af3d8a1b986fe9b43b8966797653a76ca4
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=341
CVE: NA

--------------------------------

[ Upstream commit 1dde47a6 ]

We spotted a bug recently during a review where a driver was
unregistering a bus that wasn't registered, which would trigger this
BUG_ON().  Let's handle that situation more gracefully, and just print
a warning and return.

Reported-by: Russell King (Oracle) <rmk+kernel(a)armlinux.org.uk>
Signed-off-by: Dan Carpenter <dan.carpenter(a)oracle.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel(a)armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew(a)lunn.ch>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
Signed-off-by: wangqing <wangqing(a)uniontech.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/phy/mdio_bus.c

@@ -608,7 +608,8 @@ void mdiobus_unregister(struct mii_bus *bus)
 	struct mdio_device *mdiodev;
 	int i;
 
-	BUG_ON(bus->state != MDIOBUS_REGISTERED);
+	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
+		return;
 	bus->state = MDIOBUS_UNREGISTERED;
 
 	for (i = 0; i < PHY_MAX_ADDR; i++) {