supernova: nrt - allocate sc_synth content from os
supernova: reorder priority to allow the use of SCHED_DEADLINE

Signed-off-by: Tim Blechmann <tim@klingt.org>
supernova: fix inclusion guards
supernova: improve initialization of real-time thread

Signed-off-by: Tim Blechmann <tim@klingt.org>
Merge pull request #1123 from timblechmann/for_master

some supernova fixes