CONFIG_ATARI_ETHERNAT is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

Atari EtherNAT Ethernet support


Linux Kernel Configuration
└─>Platform devices
└─>Atari EtherNAT Ethernet support
In linux kernel since version 3.1 (release Date: 2011-10-24)  
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.

is selected by