This patch adds a USB3 HCD to an existing USB2 HCD and provides
the support of SuperSpeed, in case the device can only be enumerated
with SuperSpeed.

The bulk of the added code in usb3_bos_desc and hub_control to support
SuperSpeed is borrowed from the commit 1cd8fd28 ("usb: gadget:
dummy_hcd: add SuperSpeed support").

With this patch, each vhci will have VHCI_HC_PORTS HighSpeed ports
and VHCI_HC_PORTS SuperSpeed ports.
Suggested-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>