atmel: convert tasklets to use new tasklet_setup() API

In preparation for unconditionally passing the
struct tasklet_struct pointer to all tasklet
callbacks, switch to using the new tasklet_setup()
and from_tasklet() to pass the tasklet pointer explicitly
and remove .data field.
Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200817090637.26887-6-allen.cryptic@gmail.com

drivers/net/wireless/atmel/at76c50x-usb.c

@@ -1199,7 +1199,6 @@ static void at76_rx_callback(struct urb *urb)
 {
 	struct at76_priv *priv = urb->context;
 
-	priv->rx_tasklet.data = (unsigned long)urb;
 	tasklet_schedule(&priv->rx_tasklet);
 }
 
@@ -1545,10 +1544,10 @@ static inline int at76_guess_freq(struct at76_priv *priv)
 	return ieee80211_channel_to_frequency(channel, NL80211_BAND_2GHZ);
 }
 
-static void at76_rx_tasklet(unsigned long param)
+static void at76_rx_tasklet(struct tasklet_struct *t)
 {
-	struct urb *urb = (struct urb *)param;
-	struct at76_priv *priv = urb->context;
+	struct at76_priv *priv = from_tasklet(priv, t, rx_tasklet);
+	struct urb *urb = priv->rx_urb;
 	struct at76_rx_buffer *buf;
 	struct ieee80211_rx_status rx_status = { 0 };
 
@@ -2215,7 +2214,7 @@ static struct at76_priv *at76_alloc_new_device(struct usb_device *udev)
 	INIT_WORK(&priv->work_join_bssid, at76_work_join_bssid);
 	INIT_DELAYED_WORK(&priv->dwork_hw_scan, at76_dwork_hw_scan);
 
-	tasklet_init(&priv->rx_tasklet, at76_rx_tasklet, 0);
+	tasklet_setup(&priv->rx_tasklet, at76_rx_tasklet);
 
 	priv->pm_mode = AT76_PM_OFF;
 	priv->pm_period = 0;