kvm: fix warning for non-x86 builds

Fix the following sparse warning by moving the prototype
of kvm_arch_mmu_notifier_invalidate_range() to linux/kvm_host.h .

  CHECK   arch/s390/kvm/../../../virt/kvm/kvm_main.c
arch/s390/kvm/../../../virt/kvm/kvm_main.c:138:13: warning: symbol 'kvm_arch_mmu_notifier_invalidate_range' was not declared. Should it be static?
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1464,7 +1464,4 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
 #define put_smstate(type, buf, offset, val)                      \
 	*(type *)((buf) + (offset) - 0x7e00) = val
 
-void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
-		unsigned long start, unsigned long end);
-
 #endif /* _ASM_X86_KVM_HOST_H */

include/linux/kvm_host.h

@@ -1273,4 +1273,7 @@ static inline long kvm_arch_vcpu_async_ioctl(struct file *filp,
 }
 #endif /* CONFIG_HAVE_KVM_VCPU_ASYNC_IOCTL */
 
+void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
+		unsigned long start, unsigned long end);
+
 #endif