can: ti_hecc: add missing state changes

While the ti_hecc has interrupts to report when the error counters increase
to a certain level and which change state it doesn't handle the case that
the error counters go down again, so the reported state can actually be
wrong. Since there is no interrupt for that, do update state based on the
error counters, when the state is not error active and goes down again.

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>