power: supply: bq256xx: Fix use-after-free in power_supply_changed()

In the Linux kernel, the following vulnerability has been resolved:

power: supply: bq256xx: Fix use-after-free in power_supply_changed()

Using the `devm_` variant for requesting IRQ _before_ the `devm_`

variant for allocating/registering the `power_supply` handle, means that

the `power_supply` handle will be deallocated/unregistered _before_ the

interrupt handler (since `devm_` naturally deallocates in reverse

allocation order). This means that during removal, there is a race

condition where an interrupt can fire just _after_ the `power_supply`

handle has been freed, *but* just _before_ the corresponding

unregistration of the IRQ handler has run.

This will lead to the IRQ handler calling `power_supply_changed()` with

a freed `power_supply` handle. Which usually crashes the system or

otherwise silently corrupts the memory...

Note that there is a similar situation which can also happen during

`probe()`; the possibility of an interrupt firing _before_ registering

the `power_supply` handle. This would then lead to the nasty situation

of using the `power_supply` handle *uninitialized* in

`power_supply_changed()`.

Fix this racy use-after-free by making sure the IRQ is requested _after_

the registration of the `power_supply` handle.