KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configs

The symbol was missing a KVM dependency.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 9f8014d..7a79b68 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -46,7 +46,7 @@
 
 config KVM_COMPAT
        def_bool y
-       depends on COMPAT && !S390
+       depends on KVM && COMPAT && !S390
 
 config HAVE_KVM_IRQ_BYPASS
        bool