QDSP6: Fix compile and add missing files

This commit fixs compile of QDSP6 by adding missing definitions in "linux/msm_audio.h", removing a
redefinition in "arch/arm/mach-msm/qdsp6/pcm_in.c", and adding files below from nikez 3.0.16 kernel

- include/linux/msm_q6vdec.h
- include/linux/msm_q6venc.h