[CORE] Print error code when load balancer init fails

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] Set default priority for load balancing VCPU

There is no strong reason for having load balancing VCPU with
highest priority.

In real life systems, load balancing would would be heuritic
based and best-effort service. There could be even more high
priority threads/vcpus in real-time systems hence, set default
priority for load balancing VCPU.

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