net: Move the CMD_NET config to defconfigs

This also selects CONFIG_NET for any CONFIG_CMD_NET board.

Remove the imx default for CONFIG_NET.

This moves the config that was defined by 60296a8 (commands: add more
command entries in Kconfig).

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/glacier_ramboot_defconfig b/configs/glacier_ramboot_defconfig
index 26bee7d..f4041e8 100644
--- a/configs/glacier_ramboot_defconfig
+++ b/configs/glacier_ramboot_defconfig
@@ -5,5 +5,6 @@
 CONFIG_DEFAULT_DEVICE_TREE="glacier"
 CONFIG_SYS_EXTRA_OPTIONS="SYS_RAMBOOT,SYS_TEXT_BASE=0x01000000,SYS_LDSCRIPT=board/amcc/canyonlands/u-boot-ram.lds"
 CONFIG_CMD_SETEXPR=y
+CONFIG_CMD_NET=y
 CONFIG_OF_CONTROL=y
 CONFIG_OF_EMBED=y