serial/sunzilog: fix keyboard on SUN SPARCstation

The keyboard on my SUN SPARCstation 5 no longer worked.

    The culprint was: d4e33fac
    ("serial: Kill off NO_IRQ")

Fix up logic for no irq / irq so the keyboard works again.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/tty/serial/sunzilog.c

@@ -1581,7 +1581,7 @@ static int __init sunzilog_init(void)
 	if (err)
 		goto out_unregister_uart;
 
-	if (!zilog_irq) {
+	if (zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 		err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
 				  "zs", sunzilog_irq_chain);
@@ -1622,7 +1622,7 @@ static void __exit sunzilog_exit(void)
 {
 	platform_driver_unregister(&zs_driver);
 
-	if (!zilog_irq) {
+	if (zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 
 		/* Disable Interrupts */