DM: add deinit API for loggers

when DM exit, it is better to call deinit_loggers
to do some cleanup work.

Tracked-On: #3012
Signed-off-by: Minggui Cao <minggui.cao@intel.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>

devicemodel/include/log.h

@@ -29,6 +29,7 @@ struct logger_ops {
 };
 
 int init_logger_setting(const char *opt);
+void deinit_loggers(void);
 void output_log(uint8_t level, const char *fmt, ...);
 
 /*