Make CDXL palette opaque.

libavcodec/cdxl.c

@@ -56,7 +56,7 @@ static void import_palette(CDXLVideoContext *c, uint32_t *new_palette)
         unsigned r   = ((rgb >> 8) & 0xF) * 0x11;
         unsigned g   = ((rgb >> 4) & 0xF) * 0x11;
         unsigned b   =  (rgb       & 0xF) * 0x11;
-        AV_WN32(&new_palette[i], (r << 16) | (g << 8) | b);
+        AV_WN32(&new_palette[i], (0xFFU << 24) | (r << 16) | (g << 8) | b);
     }
 }