KVM: arm64: vgic: Free private_irqs when init fails after allocation

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic: Free private_irqs when init fails after allocation Companion to commit 250f25367b58 ("KVM: arm64: Tear down vGIC on failed vCPU creation"), which added the missing kvm_vgic_vcpu_destroy() call to the kvm_share_hyp() failure path in kvm_arch_vcpu_create(). The kvm_vgic_vcpu_init() failure path immediately above it has the same shape and still needs the same cleanup. Call kvm_vgic_vcpu_destroy() when kvm_vgic_vcpu_init() fails so private IRQs allocated before a redistributor iodev registration failure are released before the failed vCPU is freed.