USB: fix oops on disconnect in cdc-acm

This patch fixes an oops caused when during an unplug a device's table
of endpoints is zeroed before the driver is notified. A pointer to
the endpoint must be cached.

this fixes a regression caused by commit
5186ffee2320942c3dc9745f7930e0eb15329ca6
Therefore it should go into 2.6.31

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 1602324..c4a0ee8f 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -126,6 +126,8 @@
 	unsigned int ctrl_caps;				/* control capabilities from the class specific header */
 	unsigned int susp_count;			/* number of suspended interfaces */
 	int combined_interfaces:1;			/* control and data collapsed */
+	int is_int_ep:1;				/* interrupt endpoints contrary to spec used */
+	u8 bInterval;
 	struct acm_wb *delayed_wb;			/* write queued for a device about to be woken */
 };