init: create android::init:: namespace

With some small fixups along the way

Test: Boot bullhead
Test: init unit tests
Change-Id: I7beaa473cfa9397f845f810557d1631b4a462d6a
diff --git a/init/firmware_handler.h b/init/firmware_handler.h
index be9daae..e456ac4 100644
--- a/init/firmware_handler.h
+++ b/init/firmware_handler.h
@@ -19,6 +19,12 @@
 
 #include "uevent.h"
 
+namespace android {
+namespace init {
+
 void HandleFirmwareEvent(const Uevent& uevent);
 
+}  // namespace init
+}  // namespace android
+
 #endif