V4L/DVB (4219): Av7110: analog sound output of DVB-C rev 2.3

Added support for the msp34x5 audio dac. Analog sound output of
Technotrend DVB-C 2300 (aka Hauppauge Nexus-CA) works now.

Signed-off-by: Tim Kaiser <timkaiser@t-online.de>
Signed-off-by: Marco Schluessler <marco@lordzodiac.de>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>