ALSA: core: Validate compress device numbers without dynamic minors

ALSA: core: Validate compress device numbers without dynamic minors

Without CONFIG_SND_DYNAMIC_MINORS, ALSA reserves only two fixed minors
for compress devices on each card: comprD0 and comprD1.

snd_find_free_minor() currently computes the compress minor as
type + dev without validating dev first, so device numbers greater than
1 spill into the HWDEP minor range instead of failing registration.

ASoC passes rtd->id to snd_compress_new(), so this can happen on real
non-dynamic-minor builds.

Add a dedicated fixed-minor check for SNDRV_DEVICE_TYPE_COMPRESS in
snd_find_free_minor() and reject out-of-range device numbers with
-EINVAL before constructing the minor.

Also remove the stale TODO in compress_offload.c that still claims
multiple compress nodes are missing.

Fixes: 3eafc959b32f ("ALSA: core: add support for compressed devices")
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260325-alsa-compress-static-minors-v1-1-0628573bee1c@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>