ALSA: line6: Pass toneport pointer to toneport_has_led()

It is unlikely this function would ever be used in a context without a
pointer to a `struct usb_line6_toneport', so grab the device type from
it rather than having the caller do it.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>