USB: Change names of SuperSpeed ep companion descriptor structs.

Differentiate between SuperSpeed endpoint companion descriptor and the
wireless USB endpoint companion descriptor.  Make all structure names for
this descriptor have "ss" (SuperSpeed) in them.  David Vrabel asked for
this change in http://marc.info/?l=linux-usb&m=124091465109367&w=2

Reported-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>