kernelconfig_penguin
CONFIG_ATARI_ETHERNAT is not available for the default architecture x86.
Result is shown for architecture m68k

is selected by
CONFIG_SMC91X

Atari EtherNAT Ethernet support

configname: CONFIG_ATARI_ETHERNAT

Linux Kernel Configuration
└─> Platform devices
└─> Atari EtherNAT Ethernet support

Say Y to include support for the EtherNAT network adapter for the
CT/60 extension port.

To compile the actual ethernet driver, choose Y or M for the SMC91X
option in the network device section; the module will be called smc91x.