xhci: Fix possible interrupt storm with suspend failure

In the case where the xhci_suspend failed because the
controller is not halted within the delay, we see that
the xhc interrupts are not acked and is leading to
a storm of unwanted dwc3_interrupt calls.

Fix this by setting the HCD_FLAG_HW_ACCESSIBLE so that
the interrupts are acked by the xhci_irq.
Once the suspend failure happens, the device does not
respond to any new device connect/disconnect. So,
fix this by restarting the host stack by notifying the
hc_died to the dwc3 glue driver.

Change-Id: Ie383d5eacca428b123c1a071a304df54e087c42e
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>