Allow setting the number of available usb host ports for boards with
additional sanity checks to allow using the second port on devices
where it is available.
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39324 3c298f89-4303-0410-b956-a3cf2f4a3e73