V4L/DVB (4620): Fix AGC configuration for MOD3000P-based boards

While converting the configuration for the old DiB3000MC-module to the new one
a wrong AGC configuration was introduced.
This is using the old one again.

Signed-off-by: Jose Alberto Reguero <jareguero@telefonica.net>
Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>