cpufreq: governor: Avoid irq_work_queue_on() crash on non-SMP ARM

As it turns out, irq_work_queue_on() will crash if invoked on
non-SMP ARM platforms, but in fact it is not necessary to use that
function in the cpufreq governor code (as it doesn't matter to that
code which CPU will handle the irq_work), so change it to always use
irq_work_queue().

Fixes: 8fb47ff100af (cpufreq: governor: Replace timers with utilization update callbacks)
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Reported-and-tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>