Ensure that unnecessary features are powered down at the end of the
attach() function.  If the configuration requires the loop thru or
xtout features, they will remain enabled.
Thanks to Antti Palosaari for noticing the additional power consumption.
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>