ath5k: remove duplicated re-assignment to pointer 'tq'

Pointer tq is initialized with &ah->ah_txq[queue] and then a few
lines later is re-assigned the same value, hence this duplicate
assignment is redundant and can be removed.

Cleans up clang warning:
drivers/net/wireless/ath/ath5k/qcu.c:326:25: warning: Value stored
to 'tq' during its initialization is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -327,8 +327,6 @@ ath5k_hw_reset_tx_queue(struct ath5k_hw *ah, unsigned int queue)
 
 	AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
 
-	tq = &ah->ah_txq[queue];
-
 	/* Skip if queue inactive or if we are on AR5210
 	 * that doesn't have QCU/DCU */
 	if ((ah->ah_version == AR5K_AR5210) ||