Fix clang "ueventd.cpp:111:1: error: no return statement in function returning non-void".

Change-Id: I69c9e5534975bffa0fbf98ca4af50400f6b94aa0
diff --git a/init/ueventd.cpp b/init/ueventd.cpp
index 833e4fd..86621cd 100644
--- a/init/ueventd.cpp
+++ b/init/ueventd.cpp
@@ -108,6 +108,8 @@
         if (ufd.revents & POLLIN)
                handle_device_fd();
     }
+
+    return 0;
 }
 
 static int get_android_id(const char *id)