USB: Goku-S: use helper functions to determine endpoint type and direction

Use helper functions to determine the type and direction of an endpoint
instead of fiddling with bEndpointAddress and bmAttributes

Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>