st/mesa: use util_format_get_blocksize()
diff --git a/src/mesa/state_tracker/st_cb_drawpixels.c b/src/mesa/state_tracker/st_cb_drawpixels.c
index e9aee6b..ba28a22 100644
--- a/src/mesa/state_tracker/st_cb_drawpixels.c
+++ b/src/mesa/state_tracker/st_cb_drawpixels.c
@@ -319,7 +319,7 @@
 
    pipeFormat = st_mesa_format_to_pipe_format(mformat);
    assert(pipeFormat);
-   cpp = st_sizeof_format(pipeFormat);
+   cpp = util_format_get_blocksize(pipeFormat);
 
    pixels = _mesa_map_pbo_source(ctx, unpack, pixels);
    if (!pixels)