readme: update SBC links
readme: update SBC links

Signed-off-by: Christian Stewart <2314b2e3a4a1f7db165be2aafbf1efd78f28cc97@paral.in>
Signed-off-by: Robin Matulinski <818762707ec4f091a424ea503e50049a8332fa38@systemli.org>

paralin/SkiffOS,paralin/SkiffOS