usb: core: constify the struct device_type usage

Since commit aed65af1 ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
usb_device_type, usb_if_device_type, usb_ep_device_type and
usb_port_device_type variables to be constant structures as well, placing
it into read-only memory which can not be modified at runtime.

Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240218-device_cleanup-usb-v1-4-77423c4da262@marliere.net


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