tty: Update cdc_acm

The CDC ACM driver uses the tty layer correctly so needs conversion. Start by
adding and initializing the port structures.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 1f95e7a..19967cd 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -90,7 +90,8 @@
 	struct usb_interface *control;			/* control interface */
 	struct usb_interface *data;			/* data interface */
 	struct tty_struct *tty;				/* the corresponding tty */
-	struct urb *ctrlurb;			/* urbs */
+	struct tty_port port;			 	/* our tty port data */
+	struct urb *ctrlurb;				/* urbs */
 	u8 *ctrl_buffer;				/* buffers of urbs */
 	dma_addr_t ctrl_dma;				/* dma handles of buffers */
 	u8 *country_codes;				/* country codes from device */