Convert CONFIG_LPC32XX_ETH to Kconfig

This converts the following to Kconfig:
   CONFIG_LPC32XX_ETH

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index d63c0a9..a6171a7 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -423,6 +423,11 @@
 	  This driver implements a DSA switch driver for the KSZ9477 family
 	  of GbE switches using the I2C interface.
 
+config LPC32XX_ETH
+	bool "LPC32xx Ethernet MAC interface driver"
+	depends on ARCH_LPC32XX
+	default y
+
 config MVGBE
 	bool "Marvell Orion5x/Kirkwood network interface support"
 	depends on ARCH_KIRKWOOD || ARCH_ORION5X