Besides power saving, this puts the AGC output of the tda8290
to tristate. This is necessary for some hybrid boards which
don't use a multiplexer for the AGC
Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>