ALSA: Fix card refcount unbalance

There are uncovered cases whether the card refcount introduced by the
commit a0830dbd isn't properly increased or decreased:
- OSS PCM and mixer success paths
- When lookup function gets NULL

This patch fixes these places.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=50251

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>