Split out the code which prepares the cedit for use, so we can call it
from a test.
Add a log category while we are here.
Signed-off-by: Simon Glass <sjg@chromium.org>
Before adding more functions to this interface, create a new header for
the configuration editor.
Fix up the expo header guard while we are here.
Signed-off-by: Simon Glass <sjg@chromium.org>