USB: ohci: allow platform driver to specify the number of ports

This patch modifies the ohci platform driver to accept the num_ports
parameter to be set via platform_data. Setting the number of ports must be
done after the call to ohci_hcd_init().

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>