Move defaults from config_cmd_default.h to Kconfig

This sets the default commands Kconfig to match
include/config_cmd_default.h commands in the common/Kconfig and removes
them from include/configs.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
[trini: rastaban, am43xx_evm_usbhost_boot, am43xx_evm_ethboot updates]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/nitrogen6s_defconfig b/configs/nitrogen6s_defconfig
index 4f13504..b7cd09a 100644
--- a/configs/nitrogen6s_defconfig
+++ b/configs/nitrogen6s_defconfig
@@ -1,6 +1,6 @@
 CONFIG_ARM=y
 CONFIG_TARGET_NITROGEN6X=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/boundary/nitrogen6x/nitrogen6s.cfg,MX6S,DDR_MB=512"
-CONFIG_CMD_SETEXPR=y
-CONFIG_CMD_NET=y
+# CONFIG_CMD_IMLS is not set
+# CONFIG_CMD_FLASH is not set
 CONFIG_SPI_FLASH=y