mac80211: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break statements instead of
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/1a9c4e8248e76e1361edbe2471a68773d87f0b67.1605896060.git.gustavoars@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -405,6 +405,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 	case WLAN_CIPHER_SUITE_WEP104:
 		if (WARN_ON_ONCE(fips_enabled))
 			return -EINVAL;
+		break;
 	case WLAN_CIPHER_SUITE_CCMP:
 	case WLAN_CIPHER_SUITE_CCMP_256:
 	case WLAN_CIPHER_SUITE_AES_CMAC:
@@ -3297,6 +3298,7 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
 			if (cfg80211_get_chandef_type(&params->chandef) !=
 			    cfg80211_get_chandef_type(&sdata->u.ibss.chandef))
 				return -EINVAL;
+			break;
 		case NL80211_CHAN_WIDTH_5:
 		case NL80211_CHAN_WIDTH_10:
 		case NL80211_CHAN_WIDTH_20_NOHT: