ASoC: msm: Add 4 front ends to support Multiple playback use case

Add 4 FE to support multiple playback use case as mentioned
4 parallel pcm and 4 parallel compressed playback
1) system tone
2) local file playback
3) picture in picture channel 1
4) picture in picture channel 2

Change-Id: Ibab38f18146aeb20273546005586846a59d1cd46
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>