USB: Fix usb_fill_int_urb for SuperSpeed devices

USB 3 and Wireless USB specify a logarithmic encoding of the endpoint
interval that matches the USB 2 specification.  usb_fill_int_urb() didn't
know that and was filling in the interval as if it was USB 1.1.  Fix
usb_fill_int_urb() for SuperSpeed devices, but leave the wireless case
alone, because David Vrabel wants to keep the old encoding.

Update the struct urb kernel doc to note that SuperSpeed URBs must have
urb->interval specified in microframes.

Add a missing break statement in the usb_submit_urb() interrupt URB
checking, since wireless USB and SuperSpeed USB encode urb->interval
differently.  This allows xHCI roothubs to actually register with khubd.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>