init: core: Add log after first boot

This patch is adding a single log message after secondary core is
initialized.

Motivation for that is to allow a simple way of testing that memory
window logging is properly working on secondary cores as well. This is
the simplest solution to allow testing in a simple and quick flow,
without creating modules and pipelines on secondary cores.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

src/init/init.c

@@ -154,6 +154,8 @@ __cold int secondary_core_init(struct sof *sof)
 
 	trace_point(TRACE_BOOT_PLATFORM);
 
+	LOG_INF("init done");
+
 	return err;
 }