Fastbootd: flashing certification

Change-Id: I564086908942463eebee69449d484ba03effc50e
diff --git a/fastbootd/commands/flash.h b/fastbootd/commands/flash.h
index 8ffd688..86dc811 100644
--- a/fastbootd/commands/flash.h
+++ b/fastbootd/commands/flash.h
@@ -58,5 +58,7 @@
     return readcount;
 }
 
+int flash_validate_certificate(int signed_fd, int *data_fd);
+
 #endif