adds ata_idle_notify system which allows callbacks in apps/ to be called

when the hard disk is idle but spinning, and just before shutting down.
on SWCODEC targets with > 8MB RAM the playback engine will try to
refill the buffer if it is less than 75% full while the disk is spinning
(temporarily disabled on the nano)


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11451 a1c6a512-1295-4272-9138-f99709370657

apps/main.c

@@ -19,6 +19,7 @@
 #include "config.h"
 
 #include "ata.h"
+#include "ata_idle_notify.h"
 #include "disk.h"
 #include "fat.h"
 #include "lcd.h"
@@ -364,6 +365,7 @@ void init(void)
     }
 #endif
 
+    ata_idle_notify_init();
     rc = ata_init();
     if(rc)
     {