Revert "char: misc: assign file->private_data in all cases"

This reverts commit 585d98e00ba7a5e2abe65f7a1eff631cb612289b, as it
breaks the FUSE misc driver.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/misc.c

@@ -143,8 +143,8 @@ static int misc_open(struct inode * inode, struct file * file)
 	err = 0;
 	old_fops = file->f_op;
 	file->f_op = new_fops;
-	file->private_data = c;
 	if (file->f_op->open) {
+		file->private_data = c;
 		err=file->f_op->open(inode,file);
 		if (err) {
 			fops_put(file->f_op);