Fix return value of dlt_log_init function (#728)

Author: lti9hc

include/dlt/dlt_log.h

@@ -71,7 +71,7 @@ void dlt_log_set_level(int level);
  * Initialize (external) logging facility
  * @param mode positive, 0 = log to stdout, 1 = log to syslog, 2 = log to file, 3 = log to stderr
  */
-void dlt_log_init(int mode);
+DltReturnValue dlt_log_init(int mode);
 
 /**
  * Initialize (external) logging facility

src/shared/dlt_log.c

@@ -77,9 +77,9 @@ void dlt_log_set_level(int level)
     }
 }
 
-void dlt_log_init(int mode)
+DltReturnValue dlt_log_init(int mode)
 {
-    dlt_log_init_multiple_logfiles_support((DltLoggingMode)mode, false, 0, 0);
+    return dlt_log_init_multiple_logfiles_support((DltLoggingMode)mode, false, 0, 0);
 }