omap: overo: update support for Micron 1GB POP

Signed-off-by: Ash Charles <ashcharles@gmail.com>
diff --git a/board/overo/overo.h b/board/overo/overo.h
index 88e197d..64604de 100644
--- a/board/overo/overo.h
+++ b/board/overo/overo.h
@@ -21,6 +21,7 @@
 #define REVISION_0	0x0
 #define REVISION_1	0x1
 #define REVISION_2	0x2
+#define REVISION_3	0x3
 
 /*
  * IEN  - Input Enable