msm: ipc_logging: move deserialize function

To enable testing using dynamically-loaded kernel modules, the
deserialization function is needed which requires it to be exported.

Rename function, move it to the main driver file and export it.

Change-Id: I5f49ebf9e9268c9e2c04fc61703a9beb6ec5f242
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>