ARM: mvebu: Convert CONFIG_MVNETA to Kconfig

This converts the following to Kconfig:
   CONFIG_MVNETA

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/configs/maxbcm_defconfig b/configs/maxbcm_defconfig
index 131d5e1..5efaff3 100644
--- a/configs/maxbcm_defconfig
+++ b/configs/maxbcm_defconfig
@@ -32,8 +32,8 @@
 CONFIG_SPI_FLASH_MACRONIX=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_STMICRO=y
-CONFIG_PHYLIB=y
 CONFIG_PHY_GIGE=y
+CONFIG_MVNETA=y
 CONFIG_DEBUG_UART_BASE=0xd0012000
 CONFIG_DEBUG_UART_CLOCK=250000000
 CONFIG_DEBUG_UART_SHIFT=2