Build tftpboot and nonlinux on x86_64

Yaakov Selkowitzrequested to merge
yselkowitz1/centos_rpms_syslinux:c10s into c10s

Merge Request Required Information

Summary of Changes

The nonlinux and tftpboot subpackages are missing since the disablement of i686 in c10s; this is a backport from rawhide:

https://src.fedoraproject.org/rpms/syslinux/c/8a16796734d896353364149c734370431fca98c8?branch=rawhide

Approved Development Ticket

https://issues.redhat.com/browse/RHEL-49795

Merge request reports