can: move can_stats.bus_off++ from can_bus_off into can_change_state

In order to be able to move the stats increment from can_bus_off() into
can_change_state(), the increment had to be moved back into code that was using
can_bus_off() but not can_change_state().

As a side-effect, this patch fixes the following bugs:
 * Redundant call to can_bus_off() in c_can.
 * Bus-off counted twice in xilinx_can.

Signed-off-by: Andri Yngvason <andri.yngvason@marel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 3ec8f6f..e54dbc1a 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -289,6 +289,8 @@
 		priv->can_stats.error_passive++;
 		break;
 	case CAN_STATE_BUS_OFF:
+		priv->can_stats.bus_off++;
+		break;
 	default:
 		break;
 	};
@@ -544,7 +546,6 @@
 	netdev_dbg(dev, "bus-off\n");
 
 	netif_carrier_off(dev);
-	priv->can_stats.bus_off++;
 
 	if (priv->restart_ms)
 		mod_timer(&priv->restart_timer,