media: si2157: add detection of si2177 tuner

Works in ATSC and QAM as is, DVB is completely untested.

Firmware required.

Signed-off-by: Brad Love <brad@nextdimension.cc>
Reviewed-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>