add ~riscv keyword
tatt report: USE tests started on Wed Feb 15 23:24:17 CST 2023 FEATURES=' test' USE='' succeeded for =sys-apps/s6-2.11.2.0 USE='-execline' succeeded for =sys-apps/s6-2.11.2.0 USE='execline' succeeded for =sys-apps/s6-2.11.2.0 this software has been used in many software's service
riscv done all arches done