usb: dwc2: Do not mix data toggle for IN and OUT endpoints, check bounds

USB protocol allows for 16 IN and 16 OUT endpoints (USB 2.0 Spec,
8.3.2.2 Endpoint Field). A function may have an EP 1 for both IN and OUT,
so these two should be kept separate. As EPs are either BULK or INTERRUPT
(or ISO), it is fine to have one array per direction for all transfer
types (also see e236519b).

USB device address is 7 bits, so a bus may have more than 16 devices.
Check the device number, as the DWC2 driver only supports BULK/ISO for
the first 16 devices.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>