USB: Unbreak fsl_usb2_udc

Commit a4e3ef5... (USB: gadget: gadget_is_{dualspeed,otg} predicates
and cleanup) broke fsl_usb2_udc; the build test didn't cover peripheral
drivers, just gadget drivers.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>