iwlwifi: mvm: Fix an error code in iwl_mvm_up()

Return -ENODEV instead of success on this error path.

Fixes: dd36a507 ("iwlwifi: mvm: look for the first supported channel when add/remove phy ctxt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210816183930.GA2068@kiliSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -1709,8 +1709,10 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 	while (!sband && i < NUM_NL80211_BANDS)
 		sband = mvm->hw->wiphy->bands[i++];
 
-	if (WARN_ON_ONCE(!sband))
+	if (WARN_ON_ONCE(!sband)) {
+		ret = -ENODEV;
 		goto error;
+	}
 
 	chan = &sband->channels[0];