wireless: set correct mandatory rate flags

According to IEEE Std 802.11-2016 (16.2.3.4 Long PHY SIGNAL field) all of
the following rates are mandatory for a HR/DSSS PHY: 1 Mb/s, 2 Mb/s,
5.5 Mb/s and 11 Mb/s. Set IEEE80211_RATE_MANDATORY_B flag for all of these
instead of just 1 Mb/s to correctly reflect this.

Signed-off-by: Richard Schütz <rschuetz@uni-koblenz.de>
[johannes: use switch statement]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/util.c

@@ -157,32 +157,30 @@ static void set_mandatory_flags_band(struct ieee80211_supported_band *sband)
 	case NL80211_BAND_2GHZ:
 		want = 7;
 		for (i = 0; i < sband->n_bitrates; i++) {
-			if (sband->bitrates[i].bitrate == 10) {
+			switch (sband->bitrates[i].bitrate) {
+			case 10:
+			case 20:
+			case 55:
+			case 110:
 				sband->bitrates[i].flags |=
 					IEEE80211_RATE_MANDATORY_B |
 					IEEE80211_RATE_MANDATORY_G;
 				want--;
-			}
-
-			if (sband->bitrates[i].bitrate == 20 ||
-			    sband->bitrates[i].bitrate == 55 ||
-			    sband->bitrates[i].bitrate == 110 ||
-			    sband->bitrates[i].bitrate == 60 ||
-			    sband->bitrates[i].bitrate == 120 ||
-			    sband->bitrates[i].bitrate == 240) {
+				break;
+			case 60:
+			case 120:
+			case 240:
 				sband->bitrates[i].flags |=
 					IEEE80211_RATE_MANDATORY_G;
 				want--;
-			}
-
-			if (sband->bitrates[i].bitrate != 10 &&
-			    sband->bitrates[i].bitrate != 20 &&
-			    sband->bitrates[i].bitrate != 55 &&
-			    sband->bitrates[i].bitrate != 110)
+				/* fall through */
+			default:
 				sband->bitrates[i].flags |=
 					IEEE80211_RATE_ERP_G;
+				break;
+			}
 		}
-		WARN_ON(want != 0 && want != 3 && want != 6);
+		WARN_ON(want != 0 && want != 3);
 		break;
 	case NL80211_BAND_60GHZ:
 		/* check for mandatory HT MCS 1..4 */