brcmsmac: increase timer reference count for new timers only

commit a1fe5280 upstream.

On hardware reintialization reference count of
already existing timers would be increased again.
This leads to problems on module unloading.
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Piotr Haber <phaber@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c

@@ -1484,9 +1484,10 @@ void brcms_add_timer(struct brcms_timer *t, uint ms, int periodic)
 #endif
 	t->ms = ms;
 	t->periodic = (bool) periodic;
-	t->set = true;
-
-	atomic_inc(&t->wl->callbacks);
+	if (!t->set) {
+		t->set = true;
+		atomic_inc(&t->wl->callbacks);
+	}
 
 	ieee80211_queue_delayed_work(hw, &t->dly_wrk, msecs_to_jiffies(ms));
 }