[media] firedtv: remove obsolete ieee1394 backend code

drivers/ieee1394/ has been removed in Linux 2.6.37.  The corresponding
backend code in firedtv is no longer built in now and can be deleted.
Firedtv continues to work with drivers/firewire/.

Also, fix a Kconfig menu comment:  Removal of CONFIG_IEEE1394 made the
"Supported FireWire (IEEE 1394) Adapters" comment disappear; bring it back
with corrected dependency.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>