USB: Don't use EHCI port sempahore for USB 3.0 hubs.

USB: Don't use EHCI port sempahore for USB 3.0 hubs.

commit 0fe51aa5eee51db7c7ecd201d42a977ad79c58b6 upstream.

The EHCI host controller needs to prevent EHCI initialization when the
UHCI or OHCI companion controller is in the middle of a port reset.  It
uses ehci_cf_port_reset_rwsem to do this.  USB 3.0 hubs can't be under
an EHCI host controller, so it makes no sense to down the semaphore for
USB 3.0 hubs.  It also makes the warm port reset code more complex.

Don't down ehci_cf_port_reset_rwsem for USB 3.0 hubs.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>