V4L/DVB (9222): S2API: Add Multiple-frontend on a single adapter support.

V4L/DVB (9222): S2API: Add Multiple-frontend on a single adapter support.

A detailed description from the original patches 2 years ago:

"The WinTV-HVR3000 has a single transport bus which is shared between
a DVB-T and DVB-S modulator. These patches build on the bus acquisition
cx88 work from a few weeks ago to add support for this.

So to applications the HVR3000 looks like this:
/dev/dvb/adapter0/fe0 (cx24123 DVB-S demod)
/dev/dvb/adapter0/fe1 (cx22702 DVB-T demod)

Additional boards continue as before, eg:
/dev/dvb/adapter1/fe0 (lgdt3302 ATSC demod)

The basic change is removing the single instance of the videobuf_dvb in
cx8802_dev and saa7134_dev(?) and replacing it with a list and some
supporting functions.

*NOTE* This branch was taken before v4l-dvb was closed for 2.6.19 so
two or three current cx88 patches appear to be reversed by this tree,
this will be cleaned up in the near future. The patches missing change
the mutex handing to core->lock, fix an enumeration problem."

It should be recognised that a number of people have been maintaining
this patchset. Significant levels of Kudos to everyone one involved,
including but not limited to:

Darron Broad
Fabio M. Di Nitto
Carlo Scarfoglio
Hans Werner

Without the work of these people, and countless others, my two year old
patches would of died on the Mercurial linuxtv.org vine a long time
ago.

TODO: Revise these patches a little further so that the need for
demux1 and dvr0 is optional, not mandatory on the HVR3000.

HISTORY (darron):
This is the last update to MFE prepared by Hans which is based
upon the `scratchpad' diff created by Carlo.
All MFE work prior to that point must be attributed to Fabio
who ported and maintained Steve's original patch up to that
time.

Signed-off-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Darron Broad <darron@kewl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>