configs: Add support for SDM845 HDK handset and speaker

SDM845 HDK has a different handdset setup from other platforms.
Add specific handset and speaker paths for it to use the correct
mixer path.

Change-Id: I9c8f32442fe74a1733b15adbddd86340e091e91b
Signed-off-by: Meng Wang <mwang@codeaurora.org>