[media] si2168: do not print device is warm every-time when opened

It repeated "found a 'Silicon Labs Si2168' in warm state" everytime
when device was opened. Message is aimed to point out firmware is
downloaded, up and running. So print it only in case firmware download
is performed.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>