[media] dvb-frontends/stv0367: fix symbol rate conditions in cab_SetQamSize()

The values used for comparing symbol rates and the resulting conditional
reg writes seem wrong (rates multiplied by ten), so fix those values.
While this doesn't seem to influence operation, it should be fixed anyway.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>