xhci: Fix USB 3.0 device restart on resume.

The xHCI hub port code gets passed a zero-based port number by the USB
core.  It then adds one to in order to find a device slot by port number
and device speed by calling xhci_find_slot_id_by_port.  That function
clearly states it requires a one-based port number.  The xHCI port
status change event handler was using a zero-based port number that it
got from find_faked_portnum_from_hw_portnum, not a one-based port
number.  This lead to the doorbells never being rung for a device after
a resume, or worse, a different device with the same speed having its
doorbell rung (which could lead to bad power management in the xHCI host
controller).

This patch should be backported to kernels as old as 2.6.39.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: Andiry Xu <andiry.xu@amd.com>
Cc: stable@vger.kernel.org