ALSA: echoaudio: remove redundant assignment to variable bytes

The variable bytes is being assigned a value that is never read, it
is being re-assigned inside a following if block. The assignment is
redundant and can be removed.

Cleans up clang scan build warning:
sound/pci/echoaudio/midi.c:211:9: warning: Although the value stored
to 'bytes' is used in the enclosing expression, the value is never
actually read from 'bytes' [deadcode.DeadStores]
Signed-off-by: NColin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220302170728.1094633-1-colin.i.king@gmail.comSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/echoaudio/midi.c

@@ -208,7 +208,7 @@ static void snd_echo_midi_output_write(struct timer_list *t)
 
 	/* No interrupts are involved: we have to check at regular intervals
 	if the card's output buffer has room for new data. */
-	sent = bytes = 0;
+	sent = 0;
 	spin_lock_irqsave(&chip->lock, flags);
 	chip->midi_full = 0;
 	if (!snd_rawmidi_transmit_empty(chip->midi_out)) {