ASoC: msm: Add front ends to support concurrent offload playbacks

For the usecases where stream's post processing is needed in DSP,
the playback is offloaded at its native sample rate and channel
mode to DSP. Currently only one offload playback session is
supported on MSM8994. Add more offload or compressed front ends
in 8994 machine driver to support multiple playback sessions in
concurrent.

Change-Id: I0a77a8d03e2e86c9bed269707cc46924c3fdca3e
Signed-off-by: Subhash Chandra Bose Naripeddy <snariped@codeaurora.org>