llvmpipe: put .bmp extension on dumped image files

src/gallium/drivers/svga/svga_pipe_flush.c

@@ -56,12 +56,12 @@ static void svga_flush( struct pipe_context *pipe,
       unsigned i;
 
       for (i = 0; i < fb->nr_cbufs; i++) {
-         util_snprintf(filename, sizeof(filename), "cbuf%u_%04u", i, frame_no);
+         util_snprintf(filename, sizeof(filename), "cbuf%u_%04u.bmp", i, frame_no);
          debug_dump_surface_bmp(&svga->pipe, filename, fb->cbufs[i]);
       }
 
       if (0 && fb->zsbuf) {
-         util_snprintf(filename, sizeof(filename), "zsbuf_%04u", frame_no);
+         util_snprintf(filename, sizeof(filename), "zsbuf_%04u.bmp", frame_no);
          debug_dump_surface_bmp(&svga->pipe, filename, fb->zsbuf);
       }