Fix missing headers in libhardware/modules/sensors.

include headers missing headers from libstagefright_foundation and
libhardware.

Bug: 33241851
Test: cd hardware/libhardware/modules/sensors/ && mma -j64 -k
BOARD_VNDK_VERSION=current
Change-Id: Ie05de74207d7c31598d2cad55ea6b7b8acace0e4
diff --git a/modules/sensors/Android.mk b/modules/sensors/Android.mk
index e5e0c9c..9942d39 100644
--- a/modules/sensors/Android.mk
+++ b/modules/sensors/Android.mk
@@ -32,6 +32,9 @@
     multihal.cpp \
     SensorEventQueue.cpp \
 
+LOCAL_HEADER_LIBRARIES := \
+    libhardware_headers \
+
 LOCAL_SHARED_LIBRARIES := \
     libcutils \
     libdl \