ALSA: line6: Remove double line6_pcm_release() after failed acquire.

If there's an error, pcm is released in line6_pcm_acquire already.

Fixes: 247d95ee ('ALSA: line6: Handle error from line6_pcm_acquire()')
Cc: <stable@vger.kernel.org> # v4.0+
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Andrej Krutak <dev@andree.sk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>