Fix i386 nmi_watchdog that does not meet watchdog timeout condition.  It
does not hit die_nmi when it should be triggered, because the current
nmi_watchdog_tick in arch/i386/kernel/nmi.c never count up alert_counter
like this:

	void nmi_watchdog_tick (struct pt_regs * regs) {
	if (last_irq_sums[cpu] == sum) {
		alert_counter[cpu]++;		<- count up alert_counter, but
		if (alert_counter[cpu] == 5*nmi_hz)
			die_nmi(regs, "NMI Watchdog detected LOCKUP");
		alert_counter[cpu] = 0;		<- reset alert_counter

This patch changes it back to the previous and working version.

This was found and originally written by Kohta NAKASHIMA.

(akpm: also uninline write_watchdog_counter(), saving 184 byets)
Signed-off-by: NGOTO Masanori <gotom@sanori.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>