community/k3s: disable on riscv64
I would prefer to fix this but disabling riscv64
for now to unlock the package builder.
go: downloading github.com/golang/mock v1.6.0
# github.com/marten-seemann/tcp
../../../../go/github.com/marten-seemann/tcp@v0.0.0-20210406111302-dfbc87cc63fd/sys_linux.go:8:19: undefined: sysSIOCINQ
../../../../go/github.com/marten-seemann/tcp@v0.0.0-20210406111302-dfbc87cc63fd/sys_linux.go:9:19: undefined: sysSIOCOUTQ
>>> ERROR: k3s: build failed