drivers: udc_stm32: remove wrong header and fix udc_ep_enable()

Driver includes wrong header zephyr/usb/usb_device.h and uses defines
from include/zephyr/drivers/usb/usb_dc.h.
Also fix udc_ep_enable() implementation in general. HAL_PCD_EP_Open()
takes the ep_type parameter as uint8_t integer type and the shim driver
should not just pass int type.
It is recommended that drivers use ep_cfg or cfg for struct
udc_ep_config, fix this as well.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>