ath5k: remove unused ah_txq_isr_qcburn member from struct ath5k_hw

Remove unused ah_txq_isr_qcburn 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/20220110223021.17655-2-ps.report@gmx.net

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

@@ -1397,7 +1397,6 @@ struct ath5k_hw {
 	u32			ah_txq_isr_txok_all;
 	u32			ah_txq_isr_txurn;
 	u32			ah_txq_isr_qcborn;
-	u32			ah_txq_isr_qcburn;
 
 	u32			*ah_rf_banks;
 	size_t			ah_rf_banks_size;

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

@@ -716,11 +716,8 @@ ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask)
 		}
 
 		/* A queue got CBR underrun */
-		if (unlikely(pisr & (AR5K_ISR_QCBRURN))) {
+		if (unlikely(pisr & (AR5K_ISR_QCBRURN)))
 			*interrupt_mask |= AR5K_INT_QCBRURN;
-			ah->ah_txq_isr_qcburn |= AR5K_REG_MS(sisr3,
-						AR5K_SISR3_QCBRURN);
-		}
 
 		/* A queue got triggered */
 		if (unlikely(pisr & (AR5K_ISR_QTRIG)))