arm: autosmp: minor corrections and optimizations

- avoid calling msecs_to_jiffies at every cycle while delay is same
- use for_each_present_cpu instead of generic for loop
- cpu is unsigned int
- make sure max_cpus is initially nr_cpu_ids as reported by smp.c
- use max_cpus in resume function instead of nr_cpu_ids

Conflicts:

	arch/arm/kernel/autosmp.c