target/i386: hyperv: add stub for hyperv_syndbg_query_options

Building without CONFIG_HYPERV is currently broken due to a missing
symbol 'hyperv_syndbg_query_options'.  Add it to the stubs
that exist for that very reasons.

Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/kvm/hyperv-stub.c

@@ -56,3 +56,8 @@ void hyperv_x86_synic_update(X86CPU *cpu)
 void hyperv_x86_set_vmbus_recommended_features_enabled(void)
 {
 }
+
+uint64_t hyperv_syndbg_query_options(void)
+{
+    return 0;
+}