[media] dvb-core: add support for a DVBv5 get_frontend() callback

Creates a DVBv5 get_frontend call, renaming the DVBv3 one to
get_frontend_legacy(), while not all frontends are converted.

After the conversion for all drivers, get_frontend_legacy()
will be removed.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/tda10071.c b/drivers/media/dvb/frontends/tda10071.c
index 7bffa65..e9e00ea 100644
--- a/drivers/media/dvb/frontends/tda10071.c
+++ b/drivers/media/dvb/frontends/tda10071.c
@@ -1248,7 +1248,7 @@
 	.sleep = tda10071_sleep,
 
 	.set_frontend_legacy = tda10071_set_frontend,
-	.get_frontend = tda10071_get_frontend,
+	.get_frontend_legacy = tda10071_get_frontend,
 
 	.read_status = tda10071_read_status,
 	.read_snr = tda10071_read_snr,