ALSA: usb-audio: Fix incorrect NULL check in create_yamaha_midi_quirk()

ALSA: usb-audio: Fix incorrect NULL check in create_yamaha_midi_quirk()

The commit 3495fe1fe91b ("ALSA: usb-audio: Fix possible NULL
dereference at create_yamaha_midi_quirk()") added NULL checks in
create_yamaha_midi_quirk(), but there was an overlook.  The code
allows one of either injd or outjd is NULL, but the second if check
made returning -ENODEV if any of them is NULL.  Fix it in a proper
form.

Fixes: 3495fe1fe91b ("ALSA: usb-audio: Fix possible NULL dereference at create_yamaha_midi_quirk()")
Reported-by: Pavel Machek <pavel@denx.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191113111259.24123-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>