rtlwifi: use work for lps

Leaving leisure power save mode can take some time, so it's better to
perform that action in process context with interrupts enabled. This
patch changes lps_leave tasklet to work.

Reported-by: Philipp Dreimann <philipp@dreimann.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Mike McCormack <mikem@ring3k.org>
Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rtlwifi/wifi.h b/drivers/net/wireless/rtlwifi/wifi.h
index f3c132b..6e6353b 100644
--- a/drivers/net/wireless/rtlwifi/wifi.h
+++ b/drivers/net/wireless/rtlwifi/wifi.h
@@ -1576,7 +1576,8 @@
 	/* For SW LPS */
 	struct delayed_work ps_work;
 	struct delayed_work ps_rfon_wq;
-	struct tasklet_struct ips_leave_tasklet;
+
+	struct work_struct lps_leave_work;
 };
 
 struct rtl_debug {