boards: shields: mikroe_adc_click: include zephyr/dt-bindings/adc/adc.h

Include zephyr/dt-bindings/adc/adc.h in the shield DTS overlays to simplify
using this shield in application overlays.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

boards/shields/mikroe_adc_click/boards/lpcxpresso55s16.overlay

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/adc/adc.h>
+
 /delete-node/ &mcp3204_mikroe_adc_click;
 
 &mikrobus_spi {

boards/shields/mikroe_adc_click/mikroe_adc_click.overlay

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/adc/adc.h>
+
 &mikrobus_spi {
 	status = "okay";