IPv6: Segment Routing HMAC support

configname: CONFIG_IPV6_SEG6_HMAC

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>The IPv6 protocol
└─>IPv6: Segment Routing HMAC support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Support for HMAC signature generation and verification
of SR-enabled packets.

If unsure, say N.