Move SPARK_Mode => Off into body

Signed-off-by: Thomas Heijligen <src@posteo.de>
diff --git a/src/fs-filo-vfs.adb b/src/fs-filo-vfs.adb
index 75df52b..30f1bca 100644
--- a/src/fs-filo-vfs.adb
+++ b/src/fs-filo-vfs.adb
@@ -3,7 +3,11 @@
 
 use Interfaces.C;
 
-package body FS.FILO.VFS is
+package body FS.FILO.VFS
+with
+   SPARK_Mode => Off,
+   Convention => C
+is
 
    function C_Mount return int
    is