ALSA: usb-audio: 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.
Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Link: https://lore.kernel.org/r/20200902040221.354941-10-allen.lkml@gmail.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/midi.c

@@ -344,10 +344,9 @@ static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint *ep)
 	spin_unlock_irqrestore(&ep->buffer_lock, flags);
 }
 
-static void snd_usbmidi_out_tasklet(unsigned long data)
+static void snd_usbmidi_out_tasklet(struct tasklet_struct *t)
 {
-	struct snd_usb_midi_out_endpoint *ep =
-		(struct snd_usb_midi_out_endpoint *) data;
+	struct snd_usb_midi_out_endpoint *ep = from_tasklet(ep, t, tasklet);
 
 	snd_usbmidi_do_output(ep);
 }
@@ -1441,7 +1440,7 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi *umidi,
 	}
 
 	spin_lock_init(&ep->buffer_lock);
-	tasklet_init(&ep->tasklet, snd_usbmidi_out_tasklet, (unsigned long)ep);
+	tasklet_setup(&ep->tasklet, snd_usbmidi_out_tasklet);
 	init_waitqueue_head(&ep->drain_wait);
 
 	for (i = 0; i < 0x10; ++i)