alsa: change an SDL_LogError into SDL_LogDebug.

it is informational only and seeing ERROR on the terminal was confusing

(cherry picked from commit af8bee2dd1d4d13110aa2020dc5d2cc5275ed7d6)

src/audio/alsa/SDL_alsa_audio.c

@@ -1156,7 +1156,7 @@ static bool ALSA_OpenDevice(SDL_AudioDevice *device)
     #if SDL_ALSA_DEBUG
     snd_pcm_uframes_t bufsize;
     ALSA_snd_pcm_hw_params_get_buffer_size(cfg_ctx.hwparams, &bufsize);
-    SDL_LogError(SDL_LOG_CATEGORY_AUDIO,
+    SDL_LogDebug(SDL_LOG_CATEGORY_AUDIO,
                      "ALSA: period size = %ld, periods = %u, buffer size = %lu",
                      cfg_ctx.persize, cfg_ctx.periods, bufsize);
     #endif