V4L/DVB (13356): stv090x: fixes signal lock logic

This patch contains several fixes for the stv090x driver:
- added missing else
- use calculated timeout instead of fixed one
- use correct frequency when doing zigzag scan
- added missing read of GENCFG register

Signed-off-by: Andreas Regel <andreas.regel@gmx.de>
Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>