serial: Kill off NO_IRQ

We transform the offenders into a test of irq <= 0 which will be ok while
the ARM people get their platform sorted. Once that is done (or in a while
if they don't do it anyway) then we will change them all to !irq checks.

For arch specific drivers that are already using NO_IRQ = 0 we just test
against zero so we don't need to re-review them later.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c
index 06f6aef..c61d950 100644
--- a/drivers/tty/serial/mux.c
+++ b/drivers/tty/serial/mux.c
@@ -499,7 +499,7 @@
 		port->membase	= ioremap_nocache(port->mapbase, MUX_LINE_OFFSET);
 		port->iotype	= UPIO_MEM;
 		port->type	= PORT_MUX;
-		port->irq	= NO_IRQ;
+		port->irq	= 0;
 		port->uartclk	= 0;
 		port->fifosize	= MUX_FIFO_SIZE;
 		port->ops	= &mux_pops;