x86: APIC/SMP: downgrade the NMI watchdog for "nosmp"

If configured to use the I/O APIC, the NMI watchdog is deemed to fail if
the chip has been deactivated as a result of "nosmp".  Downgrade to the
local APIC watchdog similarly to what is done for the UP case.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/smpboot.c

@@ -1159,6 +1159,10 @@ static int __init smp_sanity_check(unsigned max_cpus)
 	if (!max_cpus) {
 		printk(KERN_INFO "SMP mode deactivated.\n");
 		smpboot_clear_io_apic();
+
+		if (nmi_watchdog != NMI_NONE && nmi_watchdog != NMI_DISABLED)
+			nmi_watchdog = NMI_LOCAL_APIC;
+
 #ifdef CONFIG_X86_32
 		connect_bsp_APIC();
 #endif