iwlwifi: mvm: look for the first supported channel when add/remove phy ctxt

Can't rely that band 2.4 is always supported by the NIC and use the
first channel in this band for the phy ctxt.
Instead, look for the first channel in the first band that is supported
Signed-off-by: Tova Mussai <tova.mussai@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/fw.c

@@ -1282,6 +1282,7 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 	int ret, i;
 	struct ieee80211_channel *chan;
 	struct cfg80211_chan_def chandef;
+	struct ieee80211_supported_band *sband = NULL;
 
 	lockdep_assert_held(&mvm->mutex);
 
@@ -1371,7 +1372,15 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 		goto error;
 
 	/* Add all the PHY contexts */
-	chan = &mvm->hw->wiphy->bands[NL80211_BAND_2GHZ]->channels[0];
+	i = 0;
+	while (!sband && i < NUM_NL80211_BANDS)
+		sband = mvm->hw->wiphy->bands[i++];
+
+	if (WARN_ON_ONCE(!sband))
+		goto error;
+
+	chan = &sband->channels[0];
+
 	cfg80211_chandef_create(&chandef, chan, NL80211_CHAN_NO_HT);
 	for (i = 0; i < NUM_PHY_CTX; i++) {
 		/*

drivers/net/wireless/intel/iwlwifi/mvm/phy-ctxt.c

@@ -289,8 +289,17 @@ void iwl_mvm_phy_ctxt_unref(struct iwl_mvm *mvm, struct iwl_mvm_phy_ctxt *ctxt)
 	if (ctxt->ref == 0) {
 		struct ieee80211_channel *chan;
 		struct cfg80211_chan_def chandef;
+		struct ieee80211_supported_band *sband = NULL;
+		enum nl80211_band band = NL80211_BAND_2GHZ;
+
+		while (!sband && band < NUM_NL80211_BANDS)
+			sband = mvm->hw->wiphy->bands[band++];
+
+		if (WARN_ON(!sband))
+			return;
+
+		chan = &sband->channels[0];
 
-		chan = &mvm->hw->wiphy->bands[NL80211_BAND_2GHZ]->channels[0];
 		cfg80211_chandef_create(&chandef, chan, NL80211_CHAN_NO_HT);
 		iwl_mvm_phy_ctxt_changed(mvm, ctxt, &chandef, 1, 1);
 	}