[media] ts2020: keep 1.06 MHz as default value for frequency_div

Changeset 9e8da9e8 added a parameter to specify the frequency
divisor, used by the driver. However, not all places are passing
this parameter. So, preserve the previous default, to avoid breaking
the existing drivers.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>