ALSA: core: Make snd_card_free() return void

ALSA: core: Make snd_card_free() return void

The function returns 0 unconditionally. Make it return void instead and
simplify all callers accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Geoff Levand <geoff@infradead.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230207191907.467756-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>