cfg80211: fix kernel-doc for cfg80211_beacon_data

The kernel-doc comment is formatted badly, resulting
in a warning:

  include/net/cfg80211.h:1188: warning: bad line: [...]

Fix that.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1185,7 +1185,7 @@ struct cfg80211_mbssid_elems {
  * @civicloc_len: Civic location data length
  * @he_bss_color: BSS Color settings
  * @he_bss_color_valid: indicates whether bss color
-	attribute is present in beacon data or not.
+ *	attribute is present in beacon data or not.
  */
 struct cfg80211_beacon_data {
 	const u8 *head, *tail;