[CORE] delay: Make loops_per_usec and loop_per_msec parameters as per-CPU

This patch removes the assumption made for SMP host that all host CPUs run at same speed.

In real world, SMP host can have per-CPU frequency scaling or symmetric CPUs running in different frequency and power domains (e.g. big.Little systems).

Having loops_per_usec and loop_per_msec as per-CPU parameters will also give more info to upcoming SMP load balancer for load balancing VCPUs on host CPUs.

The only constraint is that if frequency of any CPU in SMP host changes then we will have to do vmm_delay_recalibrate() on that CPU after frequency change.

Signed-off-by: Anup Patel <anup@brainfault.org>