power: supply: rt9467-charger: Remove "usb_type" property write support

power: supply: rt9467-charger: Remove "usb_type" property write support

The "usb_type" property must be read-only for charger power-supply devices,
see: Documentation/ABI/testing/sysfs-class-power.

But the rt9467 driver allows writing 0/1 to it to disable/enable charging.
Other charger drivers use the "status" property for this and the rt9467
code also allows writing 0/1 to its "status" property and this does
the exact same thing as writing 0/1 to its "usb_type" property.

Drop write support for the "usb_type" property making it readonly to match
the ABI documentation. If userspace wants to disable/enable charging it
can use the "status" property for this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240831142039.28830-4-hdegoede@redhat.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>