KVM: arm64: Update comment in kvm_vgic_map_resources()

vgic_v3_map_resources() returns -EBUSY if the VGIC isn't initialized,
update the comment to kvm_vgic_map_resources() to match what the function
does.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201201150157.223625-5-alexandru.elisei@arm.com

arch/arm64/kvm/vgic/vgic-init.c

@@ -419,7 +419,8 @@ int vgic_lazy_init(struct kvm *kvm)
  * Map the MMIO regions depending on the VGIC model exposed to the guest
  * called on the first VCPU run.
  * Also map the virtual CPU interface into the VM.
- * v2/v3 derivatives call vgic_init if not already done.
+ * v2 calls vgic_init() if not already done.
+ * v3 and derivatives return an error if the VGIC is not initialized.
  * vgic_ready() returns true if this function has succeeded.
  * @kvm: kvm struct pointer
  */