kernel/msm: 8974: Add audio OCMEM driver support

Add audio OCMEM driver support to exercise On-Chip
Memory (OCMEM) for low power audio and voice. The
driver is implemented as standalone and it gets
exercised based on the usecase. Also, this design
reduces the latency associated with OCMEM handshaking
protocol. The audio OCMEM driver is enabled by default
with a Kconfig option using select. Add device tree node
for audio OCMEM to retrieve platform data.

Change-Id: Iba46ce675fc03843d88cd7cf2aa9bc92fe70a955
Signed-off-by: Phani Kumar Uppalapati <phanik@codeaurora.org>