drivers: usb_dc_rpi_pico: fix toggle data1/0 on to_device control transfers

The data stage of Control transfers that are sent from Host to Device, can
be made out of multiple OUT transactions, if the amount of data to be
transmitted is larger than the endpoint size. When this happens, the DATA
pid should be toggling. The USB Device driver of the pico must correctly
prime the EP0_OUT buffer with the correct data PID, otherwise the hardware
will reject the received transaction.

Before this change the driver used to always prime EP0_OUT with a DATA1
pid.
After this change the driver only uses DATA1 pid after a setup transaction,
and then toggles the pid for each transaction.

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