CONFIG_* variables can easily be set by overriding Build/Configure.
so set NET_RANDOM_ETHADDR=y and CMD_SETEXPR=y here.
This replaces the following patches:
0001-clearfog-generate-random-MAC-address.patch
0004-clearfog-enable-setexpr-command-by-default.patch
Signed-off-by: Josua Mayer <josua.mayer97@gmail.com>