arm: juno: Enable DM_ETH

The smc911X driver is now DM enabled, so we can switch the Juno board
over to use DM_ETH for the on-board Fast Ethernet device.
Works out of the box by using the DT.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 83268659..f115fcd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1180,7 +1180,7 @@
 	select DM_SERIAL
 	select ARM_PSCI_FW
 	select PSCI_RESET
-	select DM
+	select DM_ETH
 	select BLK
 	select USB
 	select DM_USB