feat: adapt vcpu operational mode to interpret newly added states

With a set of newly introduced states for a vCPU to allow fine grain
tracking of lifecycle of a partition, we have to slightly extend the
notion of a vCPU being ON and OFF.

This patch adds necessary support and refactors helpers to interpret
if a vCPU is in ON or OFF from a operational mode perspective. For
example, VCPU_STATE_STARTING is also considered as OFF since partition
manager has not yet scheduled the vCPU on a physical CPU.

Change-Id: I03aeca4ecb83c28e6cb7897ad0e2a51b315e16b0
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
diff --git a/src/arch/aarch64/hypervisor/psci_handler.c b/src/arch/aarch64/hypervisor/psci_handler.c
index 4702301..5f571ce 100644
--- a/src/arch/aarch64/hypervisor/psci_handler.c
+++ b/src/arch/aarch64/hypervisor/psci_handler.c
@@ -169,7 +169,7 @@
 
 		vcpu_target = vm_get_vcpu(vcpu->vm, cpu_index(c));
 		vcpu_locked = vcpu_lock(vcpu_target);
-		vcpu_on(vcpu_locked, ipa_init(arg1), arg2);
+		vcpu_prepare(vcpu_locked, ipa_init(arg1), arg2);
 		vcpu_unlock(&vcpu_locked);
 
 		/*