media: dvb-bt8xx: remove duplicate code

The same code is executed regardless of whether c->frequency < 600000000
or c->frequency < 730000000 is true.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>