can: m_can: remove redundant check for pm_clock_support

m_can_clk_start() already skip starting the clock when
clock support is disabled, remove the redundant check in
m_can_class_register().

This also solves the imbalance with m_can_clk_stop() that is called
afterward in the same function before the return.
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://lore.kernel.org/all/20240104235723.46931-1-francesco@dolcini.it
[mkl: rebased to net-next/main]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/m_can.c

@@ -2312,11 +2312,9 @@ int m_can_class_register(struct m_can_classdev *cdev)
 		}
 	}
 
-	if (cdev->pm_clock_support) {
-		ret = m_can_clk_start(cdev);
-		if (ret)
-			return ret;
-	}
+	ret = m_can_clk_start(cdev);
+	if (ret)
+		return ret;
 
 	if (cdev->is_peripheral) {
 		ret = can_rx_offload_add_manual(cdev->net, &cdev->offload,