net: add MV88E6xxx DSA driver

Add a DSA driver for the MV88E6xxx compatible Ethernet switches.

Cc: Marek BehĂșn <marek.behun@nic.cz>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 7873538..62d2c03 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -473,6 +473,13 @@
 	help
 	 Driver for the LiteEth Ethernet MAC from LiteX.
 
+config MV88E6XXX
+	bool "Marvell MV88E6xxx Ethernet switch DSA driver"
+	depends on DM_DSA && DM_MDIO
+	help
+	  This driver implements a DSA switch driver for the MV88E6xxx family
+	  of Ethernet switches using the MDIO interface
+
 config MVGBE
 	bool "Marvell Orion5x/Kirkwood network interface support"
 	depends on ARCH_KIRKWOOD || ARCH_ORION5X