Allow cuttlefish to select Sensor Hal implementation

Bug: 153342179
Test: Build, run on the device
Change-Id: Ibdc2516c5ab0f0668d45a23a1382578598c333fb
diff --git a/shared/device.mk b/shared/device.mk
index 870ec91..3d2df84 100644
--- a/shared/device.mk
+++ b/shared/device.mk
@@ -331,8 +331,11 @@
 #
 # Sensors
 #
+ifeq ($(LOCAL_SENSOR_PRODUCT_PACKAGE),)
+       LOCAL_SENSOR_PRODUCT_PACKAGE := android.hardware.sensors@2.1-service.mock
+endif
 PRODUCT_PACKAGES += \
-    android.hardware.sensors@2.1-service.mock
+    $(LOCAL_SENSOR_PRODUCT_PACKAGE)
 #
 # Thermal (mock)
 #