ARM: KVM: fix vgic-disabled build

The vgic code can be disabled in Kconfig and there are dummy implementations
of most of the provided API functions for the disabled case.

However, the newly introduced kvm_vgic_destroy/kvm_vgic_vcpu_destroy
functions are lacking those dummies, resulting in this build error:

arch/arm/kvm/arm.c: In function 'kvm_arch_destroy_vm':
arch/arm/kvm/arm.c:165:2: error: implicit declaration of function 'kvm_vgic_destroy' [-Werror=implicit-function-declaration]
  kvm_vgic_destroy(kvm);
  ^
arch/arm/kvm/arm.c: In function 'kvm_arch_vcpu_free':
arch/arm/kvm/arm.c:248:2: error: implicit declaration of function 'kvm_vgic_vcpu_destroy' [-Werror=implicit-function-declaration]
  kvm_vgic_vcpu_destroy(vcpu);
  ^

This adds two inline helpers to get it to build again in this configuration.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: c1bfb577 ("arm/arm64: KVM: vgic: switch to dynamic allocation")
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

include/kvm/arm_vgic.h

@@ -331,6 +331,14 @@ static inline int kvm_vgic_create(struct kvm *kvm)
 	return 0;
 }
 
+static inline void kvm_vgic_destroy(struct kvm *kvm)
+{
+}
+
+static inline void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+}
+
 static inline int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 {
 	return 0;