iwlwifi: Fix -EIO error code that is never returned

stable inclusion
from stable-v5.10.110
commit c12692c3e97989103f0eb2891de64712ae5dc560
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c12692c3e97989103f0eb2891de64712ae5dc560

--------------------------------

[ Upstream commit c305c94b ]

Currently the error -EIO is being assinged to variable ret when
the READY_BIT is not set but the function iwlagn_mac_start returns
0 rather than ret. Fix this by returning ret instead of 0.

Addresses-Coverity: ("Unused value")
Fixes: 7335613a ("iwlwifi: move all mac80211 related functions to one place")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210907104658.14706-1-colin.king@canonical.comSigned-off-by: NLuca Coelho <luciano.coelho@intel.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/wireless/intel/iwlwifi/dvm/mac80211.c

@@ -304,7 +304,7 @@ static int iwlagn_mac_start(struct ieee80211_hw *hw)
 
 	priv->is_open = 1;
 	IWL_DEBUG_MAC80211(priv, "leave\n");
-	return 0;
+	return ret;
 }
 
 static void iwlagn_mac_stop(struct ieee80211_hw *hw)