tests: Add some basic tests for the pci_bridge checks

This adds some simple tests for the checks of correctly formatted PCI
bridge nodes.  Doesn't test all that much, but it's a start.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

tests/pci-bridge-bad1.dts

@@ -0,0 +1,16 @@
+/dts-v1/;
+
+/ {
+	compatible = "example,pci-bridge-ok";
+	#address-cells = < 2 >;
+	#size-cells = < 2 >;
+	abadname@0 {
+		device_type = "pci";
+		compatible = "example,pci-bridge";
+		#address-cells = < 3 >;
+		#size-cells = < 2 >;
+		reg = <0 0 0 0x1000>;
+		bus-range = <0 0xff>;
+		ranges = <0 0 0 0 0 0 0x10000>;
+	};
+};