ath9k: 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>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/ar5008_phy.c

@@ -583,12 +583,14 @@ static void ar5008_hw_init_chain_masks(struct ath_hw *ah)
 	case 0x5:
 		REG_SET_BIT(ah, AR_PHY_ANALOG_SWAP,
 			    AR_PHY_SWAP_ALT_CHAIN);
+		/* fall through */
 	case 0x3:
 		if (ah->hw_version.macVersion == AR_SREV_REVISION_5416_10) {
 			REG_WRITE(ah, AR_PHY_RX_CHAINMASK, 0x7);
 			REG_WRITE(ah, AR_PHY_CAL_CHAINMASK, 0x7);
 			break;
 		}
+		/* else: fall through */
 	case 0x1:
 	case 0x2:
 	case 0x7:

drivers/net/wireless/ath/ath9k/ar9002_phy.c

@@ -119,6 +119,7 @@ static int ar9002_hw_set_channel(struct ath_hw *ah, struct ath9k_channel *chan)
 				aModeRefSel = 2;
 			if (aModeRefSel)
 				break;
+			/* else: fall through */
 		case 1:
 		default:
 			aModeRefSel = 0;

drivers/net/wireless/ath/ath9k/main.c

@@ -1928,6 +1928,7 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
 	case IEEE80211_AMPDU_TX_STOP_FLUSH:
 	case IEEE80211_AMPDU_TX_STOP_FLUSH_CONT:
 		flush = true;
+		/* fall through */
 	case IEEE80211_AMPDU_TX_STOP_CONT:
 		ath9k_ps_wakeup(sc);
 		ath_tx_aggr_stop(sc, sta, tid);