ath9k: always call ath_reset from workqueue context

This makes it much easier to add further rework to avoid race conditions
between reset and other work items.
Move other functions to make ath_reset static.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 50da642..be302fb 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -777,6 +777,7 @@
 			goto error_world;
 	}
 
+	INIT_WORK(&sc->hw_reset_work, ath_reset_work);
 	INIT_WORK(&sc->hw_check_work, ath_hw_check);
 	INIT_WORK(&sc->paprd_work, ath_paprd_calibrate);
 	INIT_DELAYED_WORK(&sc->hw_pll_work, ath_hw_pll_work);