drivers: usb_dc_rpi_pico: implement remote wakeup support

This change implements the following, necessary for remote wakeup to be
supported:

- implement usb_dc_wakeup_request() call to trigger remote wakeup
- implement interrupts to detect supsended/resumed state
- implement extra logic to simulate resumed state when the resume
  is a result of remote wakeup. In this case the rp2040 chip doesn't
  send a USB_INTR_DEV_RESUME_FROM_HOST interrupt, or any other
  interrupts when the resume condition is detected to be extended
  by the upstream port, so we need to simulate this event when we
  see activity on the bus.

Signed-off-by: Purdea Andrei <andrei@purdea.ro>