[media] media: dvb-frontends: ts2020: Added in a option for frequency divider value for s600 devices

When the tuner part of the ds3000 driver was split to share code with the m88rs2000 driver, the ts2020 driver used
the frequency divider value from the m88rs2000 driver.  However the ds3000 driver requires a different value, and this
resulted in some frequecies being invisible to the tuner.  This patch adds back in the value needed for the ds3000 driver
and configured as an option in the dw2102 frontend driver.
It may also apply to su3000 devices, which use the same ds3000 driver, but for now it is only applied to the s660 device.
Signed-off-by: John Horan <knasher@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>