KVM: Avoid using CONFIG_ in userspace visible headers

Kconfig symbols are not available in userspace, and are not stripped by
headers-install.  Avoid their use by adding #defines in <asm/kvm.h> to
suit each architecture.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index 54bcf22..dc3f6cf 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -15,6 +15,7 @@
 #define __KVM_HAVE_DEVICE_ASSIGNMENT
 #define __KVM_HAVE_MSI
 #define __KVM_HAVE_USER_NMI
+#define __KVM_HAVE_GUEST_DEBUG
 
 /* Architectural interrupt line count. */
 #define KVM_NR_INTERRUPTS 256