net: Move CONFIG_E1000 options to Kconfig

Move config for the E1000 Ethernet driver to Kconfig and tidy up affected
boards.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/T1023RDB_SPIFLASH_defconfig b/configs/T1023RDB_SPIFLASH_defconfig
index e7f4525..83b14a8 100644
--- a/configs/T1023RDB_SPIFLASH_defconfig
+++ b/configs/T1023RDB_SPIFLASH_defconfig
@@ -6,3 +6,5 @@
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_FLASH is not set
 CONFIG_SPI_FLASH=y
+CONFIG_NETDEVICES=y
+CONFIG_E1000=y