add ~riscv keyword
tatt report: USE tests started on Sun Feb 12 00:58:38 CST 2023 FEATURES=' test' USE='' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='-cdrom -ffmpeg -gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='cdrom -ffmpeg -gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='-cdrom ffmpeg -gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='cdrom ffmpeg -gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='-cdrom -ffmpeg gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='cdrom -ffmpeg gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='-cdrom ffmpeg gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2 USE='cdrom ffmpeg gstreamer' succeeded for =kde-apps/kdemultimedia-meta-22.12.2
riscv done all arches done