V4L/DVB (8474): pvrusb2: Enable IR chip on HVR-1900 class devices

The Zilog IR chip on HVR-1900 devices is held in reset when the device
initializes.  We have to bring this chip out of reset before LIRC has
any chance of operating the chip.  So do it.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>