ath5k: remove unused ah_txq_isr_txurn member from struct ath5k_hw

Remove unused ah_txq_isr_txurn member from struct ath5k_hw (set in
ath5k_hw_get_isr() but never used anywhere).
Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220110223021.17655-4-ps.report@gmx.net

drivers/net/wireless/ath/ath5k/ath5k.h

@@ -1395,7 +1395,6 @@ struct ath5k_hw {
 	u32			ah_txq_imr_nofrm;
 
 	u32			ah_txq_isr_txok_all;
-	u32			ah_txq_isr_txurn;
 
 	u32			*ah_rf_banks;
 	size_t			ah_rf_banks_size;

drivers/net/wireless/ath/ath5k/dma.c

@@ -670,13 +670,6 @@ ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask)
 			ah->ah_txq_isr_txok_all |= AR5K_REG_MS(sisr1,
 						AR5K_SISR1_QCU_TXEOL);
 
-		/* Currently this is not much useful since we treat
-		 * all queues the same way if we get a TXURN (update
-		 * tx trigger level) but we might need it later on*/
-		if (pisr & AR5K_ISR_TXURN)
-			ah->ah_txq_isr_txurn |= AR5K_REG_MS(sisr2,
-						AR5K_SISR2_QCU_TXURN);
-
 		/* Misc Beacon related interrupts */
 
 		/* For AR5211 */