tty: Make vt's have a tty_port

The vt layer isn't safely handling reference counts to tty object on the input
side. Add a tty port structure to the vt layer in order to implement this using
the standard helpers.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index d7d9acd..25bf67f 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -21,6 +21,8 @@
 #define NPAR 16
 
 struct vc_data {
+	struct tty_port port;			/* Upper level data */
+
 	unsigned short	vc_num;			/* Console number */
 	unsigned int	vc_cols;		/* [#] Console size */
 	unsigned int	vc_rows;