spl: announce boot devices

spl: announce boot devices

Now that we support alternative boot devices, it can sometimes be
unclear which boot devices was actually used. Provide a function to
announce which boot devices are attempted during boot.

Signed-off-by: Nikita Kiryanov <[email protected]>
Cc: Igor Grinberg <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Simon Glass <[email protected]>
Reviewed-by: Tom Rini <[email protected]>
Reviewed-by: Simon Glass <[email protected]>