phy: ti: tusb1210: Resolve charger-det crash if charger psy is unregistered

The power_supply frame-work is not really designed for there to be
long living in kernel references to power_supply devices.

Specifically unregistering a power_supply while some other code has
a reference to it triggers a WARN in power_supply_unregister():

	WARN_ON(atomic_dec_return(&psy->use_cnt));

Folllowed by the power_supply still getting removed and the
backing data freed anyway, leaving the tusb1210 charger-detect code
with a dangling reference, resulting in a crash the next time
tusb1210_get_online() is called.

Fix this by only holding the reference in tusb1210_get_online()
freeing it at the end of the function. Note this still leaves
a theoretical race window, but it avoids the issue when manually
rmmod-ing the charger chip driver during development.

Fixes: 48969a56

 ("phy: ti: tusb1210: Add charger detection")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240406140821.18624-1-hdegoede@redhat.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>