8250: Fix lock warning (and possible crash)

Splitting the 8250 code back up to avoid a clash with the NR_IRQS removal
patch introduced a last minute bug. Put back the additional needed lines
for the old lock init

Signed-off-by: Alan Cox <alan@redhat.com>
[ Ingo also reports that this can cause a spontaneous reboot crash with
  certain configs, and sends in an identical patch ]
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/8250.c

@@ -2969,6 +2969,9 @@ static int __init serial8250_init(void)
 		"%d ports, IRQ sharing %sabled\n", nr_uarts,
 		share_irqs ? "en" : "dis");
 
+	for (i = 0; i < NR_IRQS; i++)
+		spin_lock_init(&irq_lists[i].lock);
+
 #ifdef CONFIG_SPARC
 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
 #else