init: separate out epoll into a class

Test: init_tests
Bug: 64114943
Change-Id: I5f03314773b02b9e30e8e21895b6bdcfd4909e88
diff --git a/init/Android.bp b/init/Android.bp
index a31c5a5..63f3fca 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -100,6 +100,7 @@
         "capabilities.cpp",
         "descriptors.cpp",
         "devices.cpp",
+        "epoll.cpp",
         "firmware_handler.cpp",
         "import_parser.cpp",
         "init.cpp",