boards: nxp: lpcxpresso55xxx: list USB device as supported

List USB device and USB device "next" as supported on the NXP
LPCXpresso55S16 (which uses dedicated USB RAM) and LPCXpresso55S36 (which
does not use dedicated USB RAM).

This allows testing these two implementations during CI runs.

Signed-off-by: Henrik Brix Andersen <henrik@brixandersen.dk>