Move filesystem mounting into a new "fs" init level

Devices with non-MTD storage need to override the filesystem mounting
commands in init.rc.  Moving them to a new "fs" init level allows a
custom init.<device>.rc to handle the mounting.

Change-Id: If0e655139b9734650fb798b6eb0a90e2241fc29b
diff --git a/init/init.c b/init/init.c
index 4d98cc2..65d3d84 100755
--- a/init/init.c
+++ b/init/init.c
@@ -929,6 +929,9 @@
 
         /* execute all the boot actions to get us started */
     action_for_each_trigger("init", action_add_queue_tail);
+    action_for_each_trigger("early-fs", action_add_queue_tail);
+    action_for_each_trigger("fs", action_add_queue_tail);
+    action_for_each_trigger("post-fs", action_add_queue_tail);
     drain_action_queue();
 
         /* read any property files on system or data and