DVB (2451): Add support for KWorld DVB-S 100, based on the same chips as Hauppauge

- Add support for KWorld DVB-S 100, based on the same chips as Hauppauge
Nova-S Plus (CX23883/CX24123/CX24109), without the Intersil ISL6421,
which is used for LNB control.
- LNB voltage and tone are controled by LNBDC and LNBTone bits from
register 0x29 of the CX24123 demodulator.
- The MO_GP0_IO register from CX23883 is used to turn LNB power on and off.

Signed-off-by: Vadim Catana <skystar@moldova.cc>
Acked-by: Johannes Stezenbach <js@linuxtv.org>
Signed-off-by: Michael Krufky <mkrufky@m1k.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>