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/arch/sh/mm/alignment.c b/arch/sh/mm/alignment.c
index aea1485..ec2b253 100644
--- a/arch/sh/mm/alignment.c
+++ b/arch/sh/mm/alignment.c
@@ -140,7 +140,7 @@
 static ssize_t alignment_proc_write(struct file *file,
 		const char __user *buffer, size_t count, loff_t *pos)
 {
-	int *data = PDE(file_inode(file))->data;
+	int *data = PDE_DATA(file_inode(file));
 	char mode;
 
 	if (count > 0) {