USB: xhci: Wait for host to start running.

commit ed07453f upstream.

When the run bit is set in the xHCI command register, it may take a few
microseconds for the host to start running.  We cannot ring any doorbells
until the host is actually running, so wait until the status register says
the host is running.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Shinya Saito <shinya.saito.sx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>