clearfog: GPIO: add labels for two MCP23S17 expanders

Change-Id: Idef9666f5db10e7139097460bc3fe5b6d4af74a6
diff --git a/board/czechlight/clearfog/czechlight-clearfog.dts b/board/czechlight/clearfog/czechlight-clearfog.dts
index 8408699..490b8c6 100644
--- a/board/czechlight/clearfog/czechlight-clearfog.dts
+++ b/board/czechlight/clearfog/czechlight-clearfog.dts
@@ -111,5 +111,43 @@
 		microchip,irq-mirror;
 		microchip,irq-open-drain;
 		spi-max-frequency = <10000000>;
+
+		gpio-line-names =
+			"1-A0",
+			"1-A1",
+			"1-A2",
+			"1-A3",
+			"1-A4",
+			"1-A5",
+			"1-A6",
+			"1-A7",
+
+			"1-B0",
+			"1-B1",
+			"1-B2",
+			"1-B3",
+			"1-B4",
+			"1-B5",
+			"1-B6",
+			"1-B7",
+
+			"2-A0",
+			"2-A1",
+			"2-A2",
+			"2-A3",
+			"2-A4",
+			"2-A5",
+			"2-A6",
+			"2-A7",
+
+			"2-B0",
+			"2-B1",
+			"2-B2",
+			"2-B3",
+			"2-B4",
+			"2-B5",
+			"2-B6",
+			"2-B7"
+			;
 	};
 };