kill check_acl callback of generic_permission()

its value depends only on inode and does not change; we might as
well store it in ->i_op->check_acl and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/afs/security.c b/fs/afs/security.c
index f44b9d3..745ee65 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -350,7 +350,7 @@
 	}
 
 	key_put(key);
-	ret = generic_permission(inode, mask, flags, NULL);
+	ret = generic_permission(inode, mask, flags);
 	_leave(" = %d", ret);
 	return ret;