xHCI: warm reset support

This patch adds warm reset support to xhci hub control.
It handles Set Port Feature(BH_PORT_RESET) and Clear Port Feature
(C_BH_PORT_RESET) request from usbcore.
Note warm reset is called BH reset some places in USB3.0 specification.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>