Convert lcd_activation callbacks to use the event system to allow for multiple parallel callbacks (for custom statusbar).

Increase maximum event count as we need more (I actually had a report about it during custom statusbar testing).
Removed corresponding functions from the core and plugin api. Bump min version and sort.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23302 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/ipod/video/lcd-video.c

@@ -618,7 +618,7 @@ void lcd_awake(void)
         tick_add_task(&lcd_tick);
         wakeup_wait(&(lcd_state.initwakeup), TIMEOUT_BLOCK);
 
-        lcd_activation_call_hook();
+        send_event(LCD_EVENT_ACTIVATION, NULL);
     }
 }