[media] si2168: change firmware version print from debug to info

Even firmware version is not needed to know, it is still interesting
and useful to know some cases. Due to that increase its printing to
info log level.

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