mips: convert to asm-generic/hardirq.h

Index: linux-2.6/arch/mips/include/asm/hardirq.h
===================================================================
@@ -10,15 +10,9 @@
 #ifndef _ASM_HARDIRQ_H
 #define _ASM_HARDIRQ_H
 
-#include <linux/threads.h>
-#include <linux/irq.h>
-
-typedef struct {
-	unsigned int __softirq_pending;
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
-
 extern void ack_bad_irq(unsigned int irq);
+#define ack_bad_irq ack_bad_irq
+
+#include <asm-generic/hardirq.h>
 
 #endif /* _ASM_HARDIRQ_H */