audio pre processing: test code for dual mic

Added functional test code to validate effect API for
multi mic simplementations.

Also fixed warning in AudioFlinger.

Change-Id: I07be4d2e4d17791d3626c804ba3e9f87ff26d05a
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 0ce1153..b6ac359 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -5681,7 +5681,7 @@
 
     ALOGV("openOutput(), module %d Device %x, SamplingRate %d, Format %d, Channels %x, flags %x",
               module,
-              pDevices ? *pDevices : 0,
+              (pDevices != NULL) ? (int)*pDevices : 0,
               samplingRate,
               format,
               channelMask,