can: flexcan: fix state transition regression

Update state upon any interrupt to report correct state transitions in
case the flexcan core enabled the broken error state quirk fix.

Signed-off-by: Zhu Yi <yi.zhu5@cn.bosch.com>
Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v4.11
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>