CONFIG_OCTEON_EP is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Marvell Octeon PCI Endpoint NIC Driver

modulename: octeon_ep.ko

configname: CONFIG_OCTEON_EP

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>PCI support
└─>Marvell Octeon PCI Endpoint NIC Driver
In linux kernel since version 5.2 (release Date: 2019-07-07)  
This driver supports networking functionality of Marvell's
Octeon PCI Endpoint NIC.

To know the list of devices supported by this driver, refer
documentation in

To compile this drivers as a module, choose M here. Name of the
module is octeon_ep.

source code: