V4L/DVB (9423): Though insignificant, removes an unnecessary read of the LOCK_LOSS register,

which should have happenend in the DVB-S2 mode only, but reading it as it is
for the other delivery systems causes nothing to say but LOCK_LOST, which
just causes confusion amongst users.

Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>