can: ucan: remove set but not used variable 'udev'

can: ucan: remove set but not used variable 'udev'

[ Upstream commit 207681fc5f3d5d398f106d1ae0080fc2373f707a ]

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/can/usb/ucan.c: In function 'ucan_disconnect':
drivers/net/can/usb/ucan.c:1578:21: warning:
 variable 'udev' set but not used [-Wunused-but-set-variable]
  struct usb_device *udev;

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Martin Elshuber <martin.elshuber@theobroma-systems.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>