ath9k: use per-device struct for pm_qos_* operations

The ath9k driver uses a shared pm_qos_request_list structure for all
devices. This causes the following warning if more than one device is
present in the system:

WARNING: at kernel/pm_qos_params.c:234 ath9k_init_device+0x5e8/0x6b0()
pm_qos_add_request() called for already added request
Modules linked in:
Call Trace:
[<802b1cdc>] dump_stack+0x8/0x34
[<8007dd90>] warn_slowpath_common+0x78/0xa4
[<8007de44>] warn_slowpath_fmt+0x2c/0x38
[<801b0828>] ath9k_init_device+0x5e8/0x6b0
[<801bc508>] ath_pci_probe+0x2dc/0x39c
[<80176254>] pci_device_probe+0x64/0xa4
[<8019471c>] driver_probe_device+0xbc/0x188
[<80194854>] __driver_attach+0x6c/0xa4
[<80193e20>] bus_for_each_dev+0x60/0xb0
[<80193580>] bus_add_driver+0xcc/0x268
[<80194c08>] driver_register+0xe0/0x198
[<801764e0>] __pci_register_driver+0x50/0xe0
[<80365f48>] ath9k_init+0x3c/0x6c
[<8006050c>] do_one_initcall+0xfc/0x1d8
[<80355340>] kernel_init+0xd4/0x174
[<800639a4>] kernel_thread_helper+0x10/0x18

---[ end trace 5345fc6f870564a6 ]---

This patch fixes that warning by using a separate pm_qos_request_list
sructure for each device.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 25d3ef4..1cdbdbe 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -15,7 +15,6 @@
  */
 
 #include <linux/nl80211.h>
-#include <linux/pm_qos_params.h>
 #include "ath9k.h"
 #include "btcoex.h"
 
@@ -1244,7 +1243,7 @@
 			ath9k_btcoex_timer_resume(sc);
 	}
 
-	pm_qos_update_request(&ath9k_pm_qos_req, 55);
+	pm_qos_update_request(&sc->pm_qos_req, 55);
 
 mutex_unlock:
 	mutex_unlock(&sc->mutex);
@@ -1423,7 +1422,7 @@
 
 	sc->sc_flags |= SC_OP_INVALID;
 
-	pm_qos_update_request(&ath9k_pm_qos_req, PM_QOS_DEFAULT_VALUE);
+	pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE);
 
 	mutex_unlock(&sc->mutex);