msm: synx: support for synx kernel clients

Change provides apis for kernel clients to access synx.
This ensures that synx data is not cleaned up while
there are active clients, providing a simple way
to account for kernel users.
Use new apis from the cvp kernel client to initialize
synx session.

Change-Id: I92f057db35157a414e221f63b69bf3102dc13859
Signed-off-by: Sumukh Hallymysore Ravindra <shallymy@codeaurora.org>