test: Re-enable test_ofplatdata

This was inadvertently disabled after a recent change. Re-enable it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_ofplatdata.py b/test/py/tests/test_ofplatdata.py
index 92d09b7..e9cce4d 100644
--- a/test/py/tests/test_ofplatdata.py
+++ b/test/py/tests/test_ofplatdata.py
@@ -4,7 +4,7 @@
 import pytest
 import u_boot_utils as util
 
-@pytest.mark.boardspec('sandbox')
+@pytest.mark.boardspec('sandbox_spl')
 @pytest.mark.buildconfigspec('spl_of_platdata')
 def test_spl_devicetree(u_boot_console):
     """Test content of spl device-tree"""