In Linux ehci-q Data Toggle Control bit for interrupt transactions
is preserved in Queue Head (EHCI 3.6.2). So don't set 14's bit in
qh_endpt1 and don't manage toggle bit anywhere in int transactions.

This fixes an idle issue for USB keyboards, where keys
were physically changed but barebox haven't seen them in polling
until the next USB keyboard polling occurs.

Signed-off-by: Aleksey Kuleshov <rndfax@yandex.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>