drivers: misc: pass miscdevice pointer via file private data

For misc devices, inode->i_cdev doesn't point to the device drivers own
data.  Link between file operations and device driver internal data is
lost.  Pass pointer to misc device struct via file private data for driver
open function use.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/misc.c

@@ -144,6 +144,7 @@ static int misc_open(struct inode * inode, struct file * file)
 	old_fops = file->f_op;
 	file->f_op = new_fops;
 	if (file->f_op->open) {
+		file->private_data = c;
 		err=file->f_op->open(inode,file);
 		if (err) {
 			fops_put(file->f_op);