We don't actually need to use the test FDT as the control FDT. It slows
down the test since U-Boot needs to be restarted each time.
Instead of restarting, update the test to clear memory before it loads
the FIT.
Rename the data-variable to fdt_data since is it no-longer the control
FDT.
Signed-off-by: Simon Glass <sjg@chromium.org>
1cd07d900c