msm: dsps: Move to subsystem_get/put API

Insert a shim implementation of the subsystem framework's start
stop functions. For now, just call pil_get() and pil_put() until
all drivers are moved to start/stop functions.

Change-Id: I4e8360f38fbd45697ce567969eea740c2cb4fbbc
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>