power-libperfmgr: add a DOUBLE_TAP_TO_WAKE hint

Change-Id: I656b5eb836fb0c41fed8802efa51cbae9fdbc0c0

hidl/power-libperfmgr/Power.cpp

@@ -191,8 +191,14 @@ Return<void> Power::powerHint(PowerHint_1_0 hint, int32_t data) {
     return Void();
 }
 
-Return<void> Power::setFeature(Feature /*feature*/, bool /*activate*/) {
+Return<void> Power::setFeature(Feature feature, bool activate) {
-    // Nothing to do
+    switch (feature) {
+        case Feature::POWER_FEATURE_DOUBLE_TAP_TO_WAKE:
+            updateHint("DOUBLE_TAP_TO_WAKE", activate);
+            break;
+        default:
+            break;
+    }
     return Void();
 }