[media] Rename set_frontend fops to set_frontend_legacy

Passing DVBv3 parameters to set_frontend is not fun, as the
core doesn't have any way to know if the driver is using the
v3 or v5 parameters. So, rename the callback and add a new
one to allow distinguish between a mixed v3/v5 paramenter call
from a pure v5 call.

After having all frontends to use the new way, the legacy
call can be removed.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/dvb-usb/af9005-fe.c b/drivers/media/dvb/dvb-usb/af9005-fe.c
index aa44f65..f216933 100644
--- a/drivers/media/dvb/dvb-usb/af9005-fe.c
+++ b/drivers/media/dvb/dvb-usb/af9005-fe.c
@@ -1475,7 +1475,7 @@
 	.sleep = af9005_fe_sleep,
 	.ts_bus_ctrl = af9005_ts_bus_ctrl,
 
-	.set_frontend = af9005_fe_set_frontend,
+	.set_frontend_legacy = af9005_fe_set_frontend,
 	.get_frontend = af9005_fe_get_frontend,
 
 	.read_status = af9005_fe_read_status,