V4L/DVB (5948): Adding support for the S5H1409/CX24227 8VSB/QAM demodulator.

This patch adds support for the Samsung S5H1409 demodulator, also known
as the Conexant CX24227 demodulator. 8VSB mode has been tested and QAM
has been implemented based on the spec, although it's untested.

The S5H1409 / CX24227 appears on various Hauppauge boards.

Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>