Для openSUSE Factory запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Geckito:SDK:Main/openSUSE_Factory/Geckito:SDK:Main.repo
zypper refresh
zypper install cross-riscv64-elf-gcc11-bootstrap
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Geckito:SDK:Main/15.6/Geckito:SDK:Main.repo
zypper refresh
zypper install cross-riscv64-elf-gcc11-bootstrap
Для 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Geckito:SDK:Main/15.5/Geckito:SDK:Main.repo
zypper refresh
zypper install cross-riscv64-elf-gcc11-bootstrap