Current way of having one array telling only the port speed,
and then two separate arrays with mmio addresses for usb2 and usb3 ports
requeres helper functions to transate  hw to hcd, and hcd to hw port
numbers, and is hard to expand.

Instead create a structure describing a port, including the mmio address,
the port hardware index, hcd port index, and a pointer to the roothub
it belongs to.

Create one array containing all port structures in the same order the
hardware controller sees them. Then add an array of port pointers to
each xhci hub structure pointing to the ports that belonging to the
roothub.

This way we can easily convert hw indexed port events to usb core
hcd port numbers, and vice versa usb core hub hcd port numbers
to hw index and mmio address.

Other benefit is that we can easily find the parent hcd and xhci
structure of a port structure. This is useful in debugfs where
we can give one port structure pointer as parameter and get both
the correct mmio address and xhci lock needed to set some port
parameter.
Signed-off-by: NMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>