ath6kl: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Steve deRosier <derosier@cal-sierra.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath6kl/cfg80211.c

@@ -3899,16 +3899,19 @@ int ath6kl_cfg80211_init(struct ath6kl *ar)
 	switch (ar->hw.cap) {
 	case WMI_11AN_CAP:
 		ht = true;
+		/* fall through */
 	case WMI_11A_CAP:
 		band_5gig = true;
 		break;
 	case WMI_11GN_CAP:
 		ht = true;
+		/* fall through */
 	case WMI_11G_CAP:
 		band_2gig = true;
 		break;
 	case WMI_11AGN_CAP:
 		ht = true;
+		/* fall through */
 	case WMI_11AG_CAP:
 		band_2gig = true;
 		band_5gig = true;