procfs: new helper - PDE_DATA(inode)

The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data.  Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/net/irda/vlsi_ir.c b/drivers/net/irda/vlsi_ir.c
index 2f99f88..e22cd4e 100644
--- a/drivers/net/irda/vlsi_ir.c
+++ b/drivers/net/irda/vlsi_ir.c
@@ -383,7 +383,7 @@
 
 static int vlsi_seq_open(struct inode *inode, struct file *file)
 {
-	return single_open(file, vlsi_seq_show, PDE(inode)->data);
+	return single_open(file, vlsi_seq_show, PDE_DATA(inode));
 }
 
 static const struct file_operations vlsi_proc_fops = {