ASoC: msm8974: remove duplicate definitions and rearrange code

Duplicated AFE_PORT_ID definitions are removed from header file.
Also, rearraged Back-end definitions for BE_IN and BE_OUT in
groups. This is to clean-up the code for easy readability.

Change-Id: I85a6fd11b31e2c663c31b2f591db16169a27f1ae
Signed-off-by: Banajit Goswami <bgoswa@codeaurora.org>