BugLink: http://bugs.launchpad.net/bugs/1694665

DP MST provides the capability to send multiple video and audio streams
through a single port. This requires the API's between i915 and audio
drivers to distinguish between multiple audio capable displays that can be
connected to a port. Currently only the port identity is shared in the
APIs. This patch adds support for MST with an additional parameter
'int pipe'. The existing parameter 'port' does not change it's meaning.

pipe =
	MST	: display pipe that the stream originates from
	Non-MST	: -1

Affected APIs:
struct i915_audio_component_ops
-       int (*sync_audio_rate)(struct device *, int port, int rate);
+	int (*sync_audio_rate)(struct device *, int port, int pipe,
+	     int rate);

-       int (*get_eld)(struct device *, int port, bool *enabled,
-                       unsigned char *buf, int max_bytes);
+       int (*get_eld)(struct device *, int port, int pipe,
+		       bool *enabled, unsigned char *buf, int max_bytes);

struct i915_audio_component_audio_ops
-       void (*pin_eld_notify)(void *audio_ptr, int port);
+       void (*pin_eld_notify)(void *audio_ptr, int port, int pipe);

This patch makes dummy changes in the audio drivers (thanks Libin) for
build to succeed. The audio side drivers will send the right 'pipe' values
for MST in patches that will follow.

v2:
Renamed the new API parameter from 'dev_id' to 'pipe'. (Jim, Ville)
Included Asoc driver API compatibility changes from Jeeja.
Added WARN_ON() for invalid pipe in get_saved_encoder(). (Takashi)
Added comment for av_enc_map[] definition. (Takashi)

v3:
Fixed logic error introduced while renaming 'dev_id' as 'pipe' (Ville)
Renamed get_saved_encoder() to get_saved_enc() to reduce line length

v4:
Rebased.
Parameter check for pipe < -1 values in get_saved_enc() (Ville)
Switched to for_each_pipe() in get_saved_enc() (Ville)
Renamed 'pipe' to 'dev_id' in audio side code (Takashi)

v5:
Included a comment for the dev_id arg. (Libin)
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1474488168-2343-1-git-send-email-dhinakaran.pandiyan@intel.com
(backported from commit f9318941)
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>