Move the static inline function setup_jiffies_interrupt() from
<asm/timex.h> to arch/mn10300/kernel/cevt-mn10300.c, which is its only
callsite.

This allows to remove the inclusion of <asm/hardirq.h> and <linux/irq.h>
from <asm/timex.h> and <unit/timex.h>, fixing include hell like:

  include/linux/jiffies.h:260:31: warning: "CLOCK_TICK_RATE" is not defined [-Wundef]
  include/linux/jiffies.h:260:31: warning: "CLOCK_TICK_RATE" is not defined [-Wundef]
  include/linux/jiffies.h:46:42: error: division by zero in #if
  ...
  make[4]: *** [arch/mn10300/kernel/asm-offsets.s] Error 1

and (after a quick hack for the above by defining CLOCK_TICK_RATE in
<linux/jiffies.h>):

  In file included from include/linux/notifier.h:15:0,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:718,
                 from include/linux/gfp.h:4,
                 from include/linux/irq.h:20,
                 from arch/mn10300/unit-asb2303/include/unit/timex.h:15,
                 from arch/mn10300/include/asm/timex.h:15,
                 from include/linux/timex.h:174,
                 from include/linux/jiffies.h:8,
                 from include/linux/ktime.h:25,
                 from include/linux/timer.h:5,
                 from include/linux/workqueue.h:8,
  include/linux/srcu.h:55:22: error: field 'work' has incomplete type

As a consequence, we do need a few more inclusions of <asm/irq.h>, namely
in arch/mn10300/unit-asb2303/smc91111.c and
arch/mn10300/unit-asb2305/unit-init.c.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>