ALSA: pcm: Harden the spk_alloc assumption check

If the parsed ELD has spk_alloc=0, it currently assigns the parsed ELD
spk_alloc to 0xffff. However, we should also check if there is at least
one SAD (Short audio descriptor) to enforce the assumption, as ELD
without any sad_count, is usually considered invalid for e.g. in
commit ce9778b7a0272("ALSA: hda/hdmi: Consider ELD is invalid when no
SAD is present").

Signed-off-by: Umang Jain <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/core/pcm_drm_eld.c

···
 	 * in console or for audio devices. Assume the highest speakers
 	 * configuration, to _not_ prohibit multi-channel audio playback.
 	 */
-	if (!e->spk_alloc)
+	if (!e->spk_alloc && e->sad_count)
 		e->spk_alloc = 0xffff;
 
 	return 0;