boards: nxp: add test feature 'usbd'

Commit b6b43c3e
("drivers: udc: implement udc_mcux_ehci and udc_mcux_ip3511")
introduced MCUX shim driver using UDC driver API. Add test feature
'usbd' to a few supported boards to allow Twister to select these boards
for testing during CI runs.

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