staging: lustre: fld: fixed symbol was not declared

Fixes the sparse warning:
"warning: symbol 'fld_type_proc_dir' was not declared. Should it be static?"

Also removes initialization to NULL.
Signed-off-by: Brian Vandre <bvandre@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/fld/fld_request.c

@@ -269,7 +269,7 @@ int fld_client_del_target(struct lu_client_fld *fld, __u64 idx)
 }
 EXPORT_SYMBOL(fld_client_del_target);
 
-struct proc_dir_entry *fld_type_proc_dir = NULL;
+static struct proc_dir_entry *fld_type_proc_dir;
 
 #if defined (CONFIG_PROC_FS)
 static int fld_client_proc_init(struct lu_client_fld *fld)