V4L/DVB (3315): Use correct AGC settings for DNTV Live! DVB-T Pro

- My original settings for this board were incorrect and resulted in
an increased number of signal dropouts.  Replace this with the settings
from the Windows driver.

Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>