ipc: Add support for apr over rpmsg

Add support for apr communication over rpmsg to enable
inter processor comuunication b/w APPS and ADSP for
audio usecases.

Change-Id: I834ded7f1dd709e1d9e835b852c2edc25e8607e0
Signed-off-by: Shiv Maliyappanahalli <smaliyap@codeaurora.org>

include/ipc/apr_tal.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2011, 2016-2017 The Linux Foundation. All rights reserved.
+/* Copyright (c) 2010-2011, 2016-2018 The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -74,6 +74,7 @@ int apr_tal_close(struct apr_svc_ch_dev *apr_ch);
 int apr_tal_rx_intents_config(struct apr_svc_ch_dev *apr_ch,
 		int num_of_intents, uint32_t size);
 int apr_tal_init(void);
+void apr_tal_exit(void);
 int apr_tal_start_rx_rt(struct apr_svc_ch_dev *apr_ch);
 int apr_tal_end_rx_rt(struct apr_svc_ch_dev *apr_ch);