VAAPI spu: various

Various fixes:
- lower message priority for some
- do not crash in vlc_va_spu_Get() when number of subpicture regions do not match
  the cached SPU array for this subpicture

modules/video_output/vaapi/spu.c

@@ -440,7 +440,7 @@ static va_spu_cache_t *va_spu_cache_Create(vlc_object_t *obj, vlc_va_conn_t *va,
         float global_alpha = (float)(subpicture->i_alpha * region->i_alpha / 255) / 255;
         status = vaSetSubpictureGlobalAlpha(va->p_display, vasub_cache->i_id, global_alpha);
         if (status != VA_STATUS_SUCCESS)
-            msg_Err(obj, "failed applying alpha value to subpicture");
+            msg_Warn(obj, "failed applying alpha value to subpicture");
     }
 
     if (b_chroma)
@@ -457,7 +457,7 @@ static va_spu_cache_t *va_spu_cache_Create(vlc_object_t *obj, vlc_va_conn_t *va,
         status = vaSetSubpictureChromakey(va->p_display, vasub_cache->i_id,
                                           min, max, mask);
         if (status != VA_STATUS_SUCCESS)
-            msg_Err(obj, "failed applying chroma valuesto subpicture");
+            msg_Warn(obj, "failed applying chroma values to subpicture");
     }
 
     vasub_cache->rect.i_x = region->i_x;
@@ -799,9 +799,14 @@ int vlc_va_spu_cache_Get(vlc_object_t *obj, vlc_va_spu_cache_t *spu, const unsig
         if (region->fmt.i_chroma != VLC_CODEC_RGBA)
             continue;
 
-        /* Ooh: big booboo */
+        /* Ooh: big booboo
+         * va_spu_cache_Create() failed for some of the subpicture regions. */
         if (i_sub >= count)
+#ifdef VAAPI_DEBUG
             abort();
+#else
+            goto cleanup;
+#endif
 
         va_spu_cache_t *vasubpic;
         vasubpic = (va_spu_cache_t *) vlc_array_item_at_index(&cache->subpictures, i_sub);