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/P1010RDB-PB_SPIFLASH_defconfig b/configs/P1010RDB-PB_SPIFLASH_defconfig
index b3a30e7..b390406 100644
--- a/configs/P1010RDB-PB_SPIFLASH_defconfig
+++ b/configs/P1010RDB-PB_SPIFLASH_defconfig
@@ -4,3 +4,5 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="P1010RDB_PB,SPIFLASH"
 CONFIG_SPI_FLASH=y
+CONFIG_NETDEVICES=y
+CONFIG_E1000=y