At present when CONFIG_DEBUG_DEVRES is enabled, U-Boot prints log messages
to the console with every devres allocation/free event. This causes most
tests to fail since the console output is not as expected.
In particular this prevents us from adding a device to sandbox which uses
devres in its bind method.
Move devres over to use U-Boot's logging feature instead, and add a new
category for devres.
Signed-off-by: Simon Glass <sjg@chromium.org>