Remove old comments about USB_EHCI_HCD.

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>