rtla: Use str_has_prefix() for option prefix check

The argument parsing code in timerlat_main() and osnoise_main() uses
strncmp() with a length of 1 to check if the first argument starts
with a dash, indicating an option flag was passed.

Replace this pattern with str_has_prefix() for consistency with the
rest of the codebase. While character comparison would be slightly
more efficient, using str_has_prefix() provides better readability
and maintains a uniform coding style throughout the rtla tool.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260309195040.1019085-14-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Author: walac

tools/tracing/rtla/src/osnoise.c

@@ -1210,7 +1210,7 @@ int osnoise_main(int argc, char *argv[])
 
 	if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0)) {
 		osnoise_usage(0);
-	} else if (strncmp(argv[1], "-", 1) == 0) {
+	} else if (str_has_prefix(argv[1], "-")) {
 		/* the user skipped the tool, call the default one */
 		run_tool(&osnoise_top_ops, argc, argv);
 		exit(0);

tools/tracing/rtla/src/timerlat.c

@@ -269,7 +269,7 @@ int timerlat_main(int argc, char *argv[])
 
 	if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0)) {
 		timerlat_usage(0);
-	} else if (strncmp(argv[1], "-", 1) == 0) {
+	} else if (str_has_prefix(argv[1], "-")) {
 		/* the user skipped the tool, call the default one */
 		run_tool(&timerlat_top_ops, argc, argv);
 		exit(0);