ath9k: Fix some smatch warnings

drivers/net/wireless/ath/ath9k/hif_usb.c +135 hif_usb_mgmt_cb(6) warn:
variable dereferenced before check 'cmd'
drivers/net/wireless/ath/ath9k/btcoex.c +77 ath9k_hw_init_btcoex_hw(38)
error: buffer overflow 'ah->hw_gen_timers.gen_timer_index' 32 <=
2009813776

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/btcoex.c b/drivers/net/wireless/ath/ath9k/btcoex.c
index 41ce0b1..6635c37 100644
--- a/drivers/net/wireless/ath/ath9k/btcoex.c
+++ b/drivers/net/wireless/ath/ath9k/btcoex.c
@@ -50,7 +50,7 @@
 		.bt_first_slot_time = 5,
 		.bt_hold_rx_clear = true,
 	};
-	u32 i;
+	u32 i, idx;
 	bool rxclear_polarity = ath_bt_config.bt_rxclear_polarity;
 
 	if (AR_SREV_9300_20_OR_LATER(ah))
@@ -73,8 +73,10 @@
 		SM(ATH_BTCOEX_BMISS_THRESH, AR_BT_BCN_MISS_THRESH) |
 		AR_BT_DISABLE_BT_ANT;
 
-	for (i = 0; i < 32; i++)
-		ah->hw_gen_timers.gen_timer_index[(debruijn32 << i) >> 27] = i;
+	for (i = 0; i < 32; i++) {
+		idx = (debruijn32 << i) >> 27;
+		ah->hw_gen_timers.gen_timer_index[idx] = i;
+	}
 }
 EXPORT_SYMBOL(ath9k_hw_init_btcoex_hw);