USB: ehci: paranoia, reject large control transfers

Some EHCI fault paths with large control transfers aren't coded.  Avoid
problems by rejecting transfers that may need two qTDs (16+ KB).  This is
mostly paranoia; even 4 KB transfers are rare, and most HCDs use lower
limits (so it's unlikely anyone would ever try such a thing).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>