[media] dvb core: rename the media controller entities

Prefix all DVB media controller entities with "dvb-" and use dash
instead of underline at the names.

Requested-by: Hans Verkuil <[e-mail]>

Acked-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/dvb-core/dmxdev.c

···
 	.users = 1,
 	.writers = 1,
 #if defined(CONFIG_MEDIA_CONTROLLER_DVB)
-	.name = "demux",
+	.name = "dvb-demux",
 #endif
 	.fops = &dvb_demux_fops
 };
···
 	.readers = 1,
 	.users = 1,
 #if defined(CONFIG_MEDIA_CONTROLLER_DVB)
-	.name = "dvr",
+	.name = "dvb-dvr",
 #endif
 	.fops = &dvb_dvr_fops
 };

drivers/media/dvb-core/dvb_ca_en50221.c

···
 	.readers = 1,
 	.writers = 1,
 #if defined(CONFIG_MEDIA_CONTROLLER_DVB)
-	.name = "ca_en50221",
+	.name = "dvb-ca-en50221",
 #endif
 	.fops = &dvb_ca_fops,
 };

drivers/media/dvb-core/dvb_net.c

···
 	.users = 1,
 	.writers = 1,
 #if defined(CONFIG_MEDIA_CONTROLLER_DVB)
-	.name = "dvb net",
+	.name = "dvb-net",
 #endif
 	.fops = &dvb_net_fops,
 };