sh: mach-x3proto: needs linux/irq.h.

Since commit ba84be23
("remove linux/hardirq.h from asm-generic/local.h"), the asm/irq.h
definitions that mach-x3proto/setup.c depends on are no longer available,
causing the build to die. So, include linux/irq.h explicitly.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/boards/mach-x3proto/setup.c

@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/io.h>
 #include <linux/smc91x.h>
+#include <linux/irq.h>
 #include <asm/ilsel.h>
 
 static struct resource heartbeat_resources[] = {