wifi: ath12k: Fix uninitilized variable clang warnings

Fix uninitilized variable warnings spotted during clang compilation.

Warnings:
drivers/net/wireless/ath/ath12k/mac.c:1076:8: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
drivers/net/wireless/ath/ath12k/dbring.c:272:7: warning: variable 'ring' is used uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
drivers/net/wireless/ath/ath12k/dp_rx.c:2690:34: warning: variable 'i' is uninitialized when used here [-Wuninitialized]

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0-03171-QCAHKSWPL_SILICONZ-1
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thiraviyam Mariyappan <quic_tmariyap@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20221221105529.19345-2-quic_tmariyap@quicinc.com

drivers/net/wireless/ath/ath12k/dbring.c

@@ -230,7 +230,7 @@ int ath12k_dbring_get_cap(struct ath12k_base *ab,
 int ath12k_dbring_buffer_release_event(struct ath12k_base *ab,
 				       struct ath12k_dbring_buf_release_event *ev)
 {
-	struct ath12k_dbring *ring;
+	struct ath12k_dbring *ring = NULL;
 	struct hal_srng *srng;
 	struct ath12k *ar;
 	struct ath12k_dbring_element *buff;

drivers/net/wireless/ath/ath12k/dp_rx.c

@@ -2582,7 +2582,6 @@ int ath12k_dp_rx_process(struct ath12k_base *ab, int ring_id,
 	struct sk_buff *msdu;
 	bool done = false;
 	int mac_id;
-	int i;
 	u64 desc_va;
 
 	__skb_queue_head_init(&msdu_list);
@@ -2687,7 +2686,7 @@ int ath12k_dp_rx_process(struct ath12k_base *ab, int ring_id,
 		goto exit;
 
 	/* TODO: Move to implicit BM? */
-	ath12k_dp_rx_bufs_replenish(ab, i, rx_ring, num_buffs_reaped,
+	ath12k_dp_rx_bufs_replenish(ab, 0, rx_ring, num_buffs_reaped,
 				    ab->hw_params->hal_params->rx_buf_rbm, true);
 
 	ath12k_dp_rx_process_received_packets(ab, napi, &msdu_list,

drivers/net/wireless/ath/ath12k/mac.c

@@ -1057,7 +1057,7 @@ static int ath12k_mac_op_config(struct ieee80211_hw *hw, u32 changed)
 {
 	struct ath12k *ar = hw->priv;
 	struct ieee80211_conf *conf = &hw->conf;
-	int ret;
+	int ret = 0;
 
 	mutex_lock(&ar->conf_mutex);
 
@@ -1089,7 +1089,7 @@ static int ath12k_mac_op_config(struct ieee80211_hw *hw, u32 changed)
 err_mon_del:
 	ath12k_mac_monitor_vdev_delete(ar);
 	mutex_unlock(&ar->conf_mutex);
-	return 0;
+	return ret;
 }
 
 static int ath12k_mac_setup_bcn_tmpl(struct ath12k_vif *arvif)