tracing/kprobes: Fix the description of variable length arguments

Fix the following kernel-doc warnings:

kernel/trace/trace_kprobe.c:1029: warning: Excess function parameter 'args' description in '__kprobe_event_gen_cmd_start'
kernel/trace/trace_kprobe.c:1097: warning: Excess function parameter 'args' description in '__kprobe_event_add_fields'

Refer to the usage of variable length arguments elsewhere in the kernel
code, "@..." is the proper way to express it in the description.

Link: https://lore.kernel.org/all/20231027041315.2613166-1-yujie.liu@intel.com/

Fixes: 2a588dd ("tracing: Add kprobe event command generation functions")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310190437.paI6LYJF-lkp@intel.com/
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Author: Yujie-Liu

kernel/trace/trace_kprobe.c

@@ -1007,7 +1007,7 @@ EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
  * @name: The name of the kprobe event
  * @loc: The location of the kprobe event
  * @kretprobe: Is this a return probe?
- * @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 kprobe_event_gen_cmd_start() wrapper, which automatically
@@ -1080,7 +1080,7 @@ EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
 /**
  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
  * @cmd: A pointer to the dynevent_cmd struct representing the new event
- * @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 kprobe_event_add_fields() wrapper, which