wifi: cfg80211: wext: convert return value to kernel-doc

Since I'm getting a warning here right now, fix the
kernel-doc to be "Returns:" rather than just writing
that out in the doc paragraph.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230928172905.ab3b9274bf07.If263f9f6726d6ad4661f8603e6a4485e0385d67f@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/wext-compat.c

@@ -7,7 +7,7 @@
  * we directly assign the wireless handlers of wireless interfaces.
  *
  * Copyright 2008-2009	Johannes Berg <johannes@sipsolutions.net>
- * Copyright (C) 2019-2022 Intel Corporation
+ * Copyright (C) 2019-2023 Intel Corporation
  */
 
 #include <linux/export.h>
@@ -227,7 +227,7 @@ EXPORT_WEXT_HANDLER(cfg80211_wext_giwrange);
  * cfg80211_wext_freq - get wext frequency for non-"auto"
  * @freq: the wext freq encoding
  *
- * Returns a frequency, or a negative error code, or 0 for auto.
+ * Returns: a frequency, or a negative error code, or 0 for auto.
  */
 int cfg80211_wext_freq(struct iw_freq *freq)
 {