KVM: x86: Add requisite includes to hyperv.h

Until this point vmx.c has been the only consumer and included the
file after many others.  Prepare for multiple consumers, i.e. the
shattering of vmx.c
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.h

@@ -24,6 +24,8 @@
 #ifndef __ARCH_X86_KVM_HYPERV_H__
 #define __ARCH_X86_KVM_HYPERV_H__
 
+#include <linux/kvm_host.h>
+
 static inline struct kvm_vcpu_hv *vcpu_to_hv_vcpu(struct kvm_vcpu *vcpu)
 {
 	return &vcpu->arch.hyperv;