audio policy: engine configurable: do not compile example makefile

This patch avoids compiling the example makefile of the engine
configurable settings and structure files. It is up to the oem
to have its own makefile with its own structure and settings files.

Change-Id: I735290bff08ca6183da7ea4266ced9206f2bb6a1
Signed-off-by: François Gaffie <francois.gaffie@intel.com>