dsp : Align module Payload to 8 bytes

DSP is expecting the payload to be 8 byte alignment but
HLOS is giving 4 byte alignment.
Due to this, command to DSP are failing.
Align module payload struct to 8 byte to fix the issue.

Change-Id: Ib804102634842f8040d0adb8491d16ceae767a6f
Signed-off-by: Rutvik Patel <prutvikr@codeaurora.org>