ARM: imx: stm32: Test whether ethernet node is enabled before reading MAC EEPROM on DHSOM

Check whether the ethernet interface is enabled at all before reading
MAC EEPROM. As a cost saving measure, it can happen that the MAC EEPROM
is not populated on SoMs which do not use ethernet.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/board/dhelectronics/dh_imx6/dh_imx6.c b/board/dhelectronics/dh_imx6/dh_imx6.c
index 07fc9b1..0676587 100644
--- a/board/dhelectronics/dh_imx6/dh_imx6.c
+++ b/board/dhelectronics/dh_imx6/dh_imx6.c
@@ -92,6 +92,9 @@
 	if (dh_mac_is_in_env("ethaddr"))
 		return 0;
 
+	if (dh_get_mac_is_enabled("ethernet0"))
+		return 0;
+
 	if (!dh_imx_get_mac_from_fuse(enetaddr))
 		goto out;