tty: serial: ip22zilog: Use platform device for probing

After commit 84a9582f ("serial: core: Start managing serial controllers
to enable runtime PM") serial drivers need to provide a device in
struct uart_port.dev otherwise an oops happens. To fix this issue
for ip22zilog driver switch driver to a platform driver and setup
the serial device in sgi-ip22 code.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: https://lore.kernel.org/r/20250725134018.136113-1-tsbogend@alpha.franken.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>