recovery: Add generic write_misc()

It is needed by other patches to get write access to MISC partition

Change-Id: Iec58833763b9d37d3f44ef8f70e5cfd2060b80da
diff --git a/app/aboot/recovery.h b/app/aboot/recovery.h
index ac291fa..0d6289a 100644
--- a/app/aboot/recovery.h
+++ b/app/aboot/recovery.h
@@ -62,7 +62,7 @@
 	unsigned fail_bitmap_length;
 };
 
-
+int write_misc(unsigned page_offset, void *buf, unsigned size);
 
 int get_recovery_message(struct recovery_message *out);
 int set_recovery_message(const struct recovery_message *in);