If flexcan_chip_start() in flexcan_open() fails, the interrupt is not freed,
this patch adds the missing cleanup.

Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

(cherry picked from commit 7e9e148a)
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>