USB: ccid_bridge: Don't kill URB in release after device is disconnected

The URBs are killed in disconnect method. If the device is disconnected
before the /dev/ccid_bridge is closed, no need to kill the URBs again.
As the URB reference count is dropped in disconnect, accessing it in
release is causing the kernel panic.

CRs-Fixed: 653776
Change-Id: I7fae9ac2568cce59ea39bdd73c955d388d3f26bd
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>