can: flexcan: flexcan_setup_stop_mode(): add missing "req_bit" to stop mode property comment

In the patch

    d9b081e3 ("can: flexcan: remove ack_grp and ack_bit handling from driver")

the unused ack_grp and ack_bit were removed from the driver. However in the
comment, the "req_bit" was accidentally removed, too.

This patch adds back the "req_bit" bit.

Fixes: d9b081e3 ("can: flexcan: remove ack_grp and ack_bit handling from driver")
Reported-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Link: http://lore.kernel.org/r/20201014114810.2911135-1-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -1852,7 +1852,7 @@ static int flexcan_setup_stop_mode(struct platform_device *pdev)
 		return -EINVAL;
 
 	/* stop mode property format is:
-	 * <&gpr req_gpr>.
+	 * <&gpr req_gpr req_bit>.
 	 */
 	ret = of_property_read_u32_array(np, "fsl,stop-mode", out_val,
 					 ARRAY_SIZE(out_val));