The Si2141 needs two distinct commands for powerup/reset, otherwise it
will not respond to chip revision requests. It also needs a firmware
to run properly.

Cc: Evgeny Plehov <EvgenyPlehov@ukr.net>
Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>