net: dsa: mt7530: fix NULL dereference on unbind of MT7531 and MT7621

In the Linux kernel, the following vulnerability has been resolved: net: dsa: mt7530: fix NULL dereference on unbind of MT7531 and MT7621 The core and io supplies are only requested for ID_MT7530: both the devm_regulator_get() in probe and the regulator_enable() in mt7530_setup() are guarded by the switch id, but mt7530_remove() disables them unconditionally. On an MT7621 or an MT7531 both pointers are still NULL from devm_kzalloc(), so rmmod or a sysfs unbind calls regulator_disable() on NULL.

Where it's fixed