[CORE] vmm_scheduler: Don't enqueue woken-up VCPU in vmm_scheduler_next()

The vmm_scheduler_state_change() function enqueues a woken-up VCPU
(i.e. VCPU put-in READY state) to ready queue hence no need to enqueue
it again in vmm_scheduler_next() function.

This patch does above described minor fix in vmm_scheduler_next()

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