fd: Sanitize fd_parms fd_name field

It used to be ulong, but it can be int now (no mapping addresses there). And the
name fd is better than fd_name (reason is the same).

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/files.h

@@ -8,7 +8,7 @@
 #include "image.h"
 
 struct fd_parms {
-	unsigned long	fd_name;
+	int		fd;
 	unsigned long	pos;
 	unsigned int	flags;
 	unsigned int	type;