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/ls2085ardb_nand_defconfig b/configs/ls2085ardb_nand_defconfig
index 8539307..96a0dfd 100644
--- a/configs/ls2085ardb_nand_defconfig
+++ b/configs/ls2085ardb_nand_defconfig
@@ -3,3 +3,5 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="SYS_FSL_DDR4,NAND"
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_NETDEVICES=y
+CONFIG_E1000=y