m68k: the one hw_irq.h can be used buy all m68k

The mmu and non-mmu hw_irq.h are identical, revert to a single copy.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/include/asm/hw_irq.h

-#ifdef __uClinux__
-#include "hw_irq_no.h"
-#else
-#include "hw_irq_mm.h"
+#ifndef __ASM_M68K_HW_IRQ_H
+#define __ASM_M68K_HW_IRQ_H
+
+/* Dummy include. */
+
 #endif

arch/m68k/include/asm/hw_irq_mm.h

-#ifndef __ASM_M68K_HW_IRQ_H
-#define __ASM_M68K_HW_IRQ_H
-
-/* Dummy include. */
-
-#endif

arch/m68k/include/asm/hw_irq_no.h

-#ifndef __M68KNOMMU_HW_IRQ_H__
-#define __M68KNOMMU_HW_IRQ_H__
-
-#endif /* __M68KNOMMU_HW_IRQ_H__ */