tty: replace ->proc_fops with ->proc_show

Just set up the show callback in the tty_operations, and use
proc_create_single_data to create the file without additional
boilerplace code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 31c2b5b..71dbc89 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -293,7 +293,7 @@ struct tty_operations {
 	int (*poll_get_char)(struct tty_driver *driver, int line);
 	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 #endif
-	const struct file_operations *proc_fops;
+	int (*proc_show)(struct seq_file *, void *);
 } __randomize_layout;
 
 struct tty_driver {