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

Cavium PTP coprocessor as PTP clock

modulename: cavium_ptp.ko

configname: CONFIG_CAVIUM_PTP

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>PCI support
└─>Cavium PTP coprocessor as PTP clock
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This driver adds support for the Precision Time Protocol Clocks and
Timestamping coprocessor (PTP) found on Cavium processors.
PTP provides timestamping mechanism that is suitable for use in IEEE 1588
Precision Time Protocol or other purposes. Timestamps can be used in
BGX, TNS, GTI, and NIC blocks.

source code: