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/mx28evk_nand_defconfig b/configs/mx28evk_nand_defconfig
index ed6137c..ee4536d 100644
--- a/configs/mx28evk_nand_defconfig
+++ b/configs/mx28evk_nand_defconfig
@@ -2,6 +2,6 @@
 CONFIG_TARGET_MX28EVK=y
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="ENV_IS_IN_NAND"
-CONFIG_CMD_SETEXPR=y
-CONFIG_CMD_NET=y
+# CONFIG_CMD_IMLS is not set
+# CONFIG_CMD_FLASH is not set
 CONFIG_SPI_FLASH=y