tracing/synthetic: fix kernel-doc warnings

scripts/kernel-doc warns about using @args: for variadic arguments to
functions. Documentation/doc-guide/kernel-doc.rst says that this should
be written as @...: instead, so update the source code to match that,
preventing the warnings.

trace_events_synth.c:1165: warning: Excess function parameter 'args' description in '__synth_event_gen_cmd_start'
trace_events_synth.c:1714: warning: Excess function parameter 'args' description in 'synth_event_trace'

Link: https://lore.kernel.org/linux-trace-kernel/20231220061226.30962-1-rdunlap@infradead.org

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 35ca5207 ("tracing: Add synthetic event command generation functions")
Fixes: 8dcc53ad ("tracing: Add synth_event_trace() and related functions")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

kernel/trace/trace_events_synth.c

@@ -1137,7 +1137,7 @@ EXPORT_SYMBOL_GPL(synth_event_add_fields);
  * @cmd: A pointer to the dynevent_cmd struct representing the new event
  * @name: The name of the synthetic event
  * @mod: The module creating the event, NULL if not created from a module
- * @args: Variable number of arg (pairs), one pair for each field
+ * @...: Variable number of arg (pairs), one pair for each field
  *
  * NOTE: Users normally won't want to call this function directly, but
  * rather use the synth_event_gen_cmd_start() wrapper, which
@@ -1695,7 +1695,7 @@ __synth_event_trace_end(struct synth_event_trace_state *trace_state)
  * synth_event_trace - Trace a synthetic event
  * @file: The trace_event_file representing the synthetic event
  * @n_vals: The number of values in vals
- * @args: Variable number of args containing the event values
+ * @...: Variable number of args containing the event values
  *
  * Trace a synthetic event using the values passed in the variable
  * argument list.