[PATCH] Enable IRQ0 for PPC4xx UART

Redefine is_real_interrupt(irq) macro,
since IRQ0 is valid for PPC4xx platform.

Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>

diff -ruN linux.orig/include/asm-ppc/serial.h linux/include/asm-ppc/serial.h
--- linux.orig/include/asm-ppc/serial.h	2007-03-16 18:04:16.000000000 +0300
+++ linux/include/asm-ppc/serial.h	2007-03-20 15:52:02.000000000 +0300
@@ -28,6 +28,9 @@
 #elif defined(CONFIG_SPRUCE)
 #include <platforms/spruce.h>
 #elif defined(CONFIG_4xx)
+/* UART IRQ0 is valid for PPC4xx */
+#undef is_real_interrupt
+#define is_real_interrupt(irq)	((irq) >= 0)
 #include <asm/ibm4xx.h>
 #elif defined(CONFIG_83xx)
 #include <asm/mpc83xx.h>