kernel/svc: Make svcCreateThread/svcStartThread/svcSleepThread/svcExitThread...

kernel/svc: Make svcCreateThread/svcStartThread/svcSleepThread/svcExitThread calls show up in the debug log

These are actually quite important indicators of thread lifetimes, so
they should be going into the debug log, rather than being treated as
misc info and delegated to the trace log.