rtla/osnoise: Distinguish missing workload option

osnoise_set_workload returns -1 for both missing OSNOISE_WORKLOAD option
and failure in setting the option.

Return -1 for missing and -2 for failure to distinguish them.

Cc: [email protected]
Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: lenticularis39

tools/tracing/rtla/src/osnoise.c

@@ -867,7 +867,7 @@ int osnoise_set_workload(struct osnoise_context *context, bool onoff)
 
 	retval = osnoise_options_set_option("OSNOISE_WORKLOAD", onoff);
 	if (retval < 0)
-		return -1;
+		return -2;
 
 	context->opt_workload = onoff;