hw/char/sh_serial: Convert to TypeInfo

hw/char/sh_serial: Convert to TypeInfo

QOM types are now registered using as TypeInfo via DEFINE_TYPES()
or type_init(). Update TYPE_SH_SERIAL, removing the empty QOM
instance_init/finalize handlers.

This was definitely wrong, because OBJECT_DEFINE_TYPE() is only
for cases where the class needs its own virtual methods or some
other per-class state in its own class struct.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20250124175053.74461-3-philmd@linaro.org>