x86: qemu: Enable writing MP table

Enable writing MP table for QEMU boads (i440fx and q35).

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/dts/qemu-x86_q35.dts b/arch/x86/dts/qemu-x86_q35.dts
index 5fbabc2..2e785fa 100644
--- a/arch/x86/dts/qemu-x86_q35.dts
+++ b/arch/x86/dts/qemu-x86_q35.dts
@@ -35,6 +35,18 @@
 		stdout-path = "/serial";
 	};
 
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "cpu-x86";
+			reg = <0>;
+			intel,apic-id = <0>;
+		};
+	};
+
 	pci {
 		compatible = "pci-x86";
 		#address-cells = <3>;