board: pm9263: switch to use DM_ETH

Enable CONFIG_DM_ETH in configs/pm9263_defconfig
Drop legacy initialization in board/ronetix/pm9263.c
Remove network related setting from include/configs/pm9263.h

Signed-off-by: Ilko Iliev <iliev@ronetix.at>
diff --git a/configs/pm9263_defconfig b/configs/pm9263_defconfig
index 817a984..ef18e74 100644
--- a/configs/pm9263_defconfig
+++ b/configs/pm9263_defconfig
@@ -50,6 +50,8 @@
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_ATMEL=y
 CONFIG_SPI_FLASH_DATAFLASH=y
+CONFIG_DM_ETH=y
+CONFIG_MACB=y
 CONFIG_DM_SERIAL=y
 CONFIG_ATMEL_USART=y
 CONFIG_SPI=y