Fix log tag for sensors VTS tests

Define log tag at build level to ensure all libraries have a tag
defined.

Bug: 135638664
Test: run VtsHalSensorsV2_0TargetTest
Change-Id: I593055b59238e9fa8dead00a3dafa84c00e90ec4
diff --git a/sensors/2.0/vts/functional/Android.bp b/sensors/2.0/vts/functional/Android.bp
index 8e8413c..98f0eac 100644
--- a/sensors/2.0/vts/functional/Android.bp
+++ b/sensors/2.0/vts/functional/Android.bp
@@ -16,6 +16,7 @@
 
 cc_test {
     name: "VtsHalSensorsV2_0TargetTest",
+    cflags: ["-DLOG_TAG=\"sensors_hidl_hal_test\""],
     defaults: ["VtsHalTargetTestDefaults"],
     srcs: [
         "SensorsHidlEnvironmentV2_0.cpp",