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/mips/lasat/picvue_proc.c b/arch/mips/lasat/picvue_proc.c
index c592bc8..638c5db 100644
--- a/arch/mips/lasat/picvue_proc.c
+++ b/arch/mips/lasat/picvue_proc.c
@@ -58,13 +58,13 @@
 
 static int pvc_line_proc_open(struct inode *inode, struct file *file)
 {
-	return single_open(file, pvc_line_proc_show, PDE(inode)->data);
+	return single_open(file, pvc_line_proc_show, PDE_DATA(inode));
 }
 
 static ssize_t pvc_line_proc_write(struct file *file, const char __user *buf,
 				   size_t count, loff_t *pos)
 {
-	int lineno = *(int *)PDE(file_inode(file))->data;
+	int lineno = *(int *)PDE_DATA(file_inode(file));
 	char kbuf[PVC_LINELEN];
 	size_t len;