boards/mcb2388: add SAUL config for ADC

ADC0 is connected to a potentiometer on the board, so expose this
through SAUL.

boards/mcb2388/Makefile.dep

@@ -1,3 +1,4 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
+  USEMODULE += saul_adc
   USEMODULE += saul_gpio
 endif

boards/mcb2388/include/adc_params.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2020 Beuth Hochschule für Technik Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup   boards_mcb2388
+ * @{
+ *
+ * @file
+ * @brief     Board specific configuration of direct mapped ADC
+ *
+ * @author    Benjamin Valentin <benpicco@beuth-hochschule.de>
+ */
+
+#ifndef ADC_PARAMS_H
+#define ADC_PARAMS_H
+
+#include "board.h"
+#include "saul/periph.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief    ADC configuration
+ */
+static const  saul_adc_params_t saul_adc_params[] =
+{
+    {
+        .name = "POT1",
+        .line = ADC_LINE(0),
+        .res  = ADC_RES_10BIT,
+    },
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ADC_PARAMS_H */
+/** @} */