ALSA: fireface: rename protocol layer for former models

In a series of Fireface, later model supports different protocol
from former models.

This commit is a preparation to support both of protocols.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/fireface/Makefile

 snd-fireface-objs := ff.o ff-transaction.o ff-midi.o ff-proc.o amdtp-ff.o \
 		     ff-stream.o ff-pcm.o ff-hwdep.o ff-protocol-ff400.o \
-		     ff-protocol-ff800.o
+		     ff-protocol-former.o
 obj-$(CONFIG_SND_FIREFACE) += snd-fireface.o

sound/firewire/fireface/ff-protocol-ff800.c → sound/firewire/fireface/ff-protocol-former.c

-/*
- * ff-protocol-ff800.c - a part of driver for RME Fireface series
- *
- * Copyright (c) 2018 Takashi Sakamoto
- *
- * Licensed under the terms of the GNU General Public License, version 2.
- */
+// SPDX-License-Identifier: GPL-2.0
+// ff-protocol-former.c - a part of driver for RME Fireface series
+//
+// Copyright (c) 2019 Takashi Sakamoto
+//
+// Licensed under the terms of the GNU General Public License, version 2.
 
 #include <linux/delay.h>