[media] dvb_frontend: add multistream support

[media] dvb_frontend: add multistream support

Unify multistream support at the DVBAPI: several delivery systems
allow it. Yet, each one had its own name. So, instead of adding
a third version of this field, remove the per-standard naming,
unifying it into a common name.

The legacy code number can still be used by old applications.

Version increased to 5.8.

[mchehab@redhat.com: joined the va1j5jf007s patch, in order to
 avoid compilation breakage]
Signed-off-by: Evgeny Plehov <EvgenyPlehov@ukr.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>