can: SJA1000 add missing spin_lock_init()

As remarked by Sam Ravnborg the spin_lock variable, that has been introduced
in commit 57c8a456640fa3ca777652f11f2db4179a3e66b6 ("can: Fix SJA1000 command
register writes on SMP systems") has not been initialized properly.

This patch adds the initialization to allow spinlock debugging.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/sja1000/sja1000.c

@@ -599,6 +599,8 @@ struct net_device *alloc_sja1000dev(int sizeof_priv)
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
 		CAN_CTRLMODE_BERR_REPORTING;
 
+	spin_lock_init(&priv->cmdreg_lock);
+
 	if (sizeof_priv)
 		priv->priv = (void *)priv + sizeof(struct sja1000_priv);