rknanoutils: add raw encode mode, add header fields

The raw encode mode allows to use the raw encode_page routine on
any file which proved to be useful. The guessed fields of the
headers are based on some rk2918 headers which leaked. They are
mainly informative though (date, version, chip).

Change-Id: I139ea0c40f76b6dde041c448bbf3e7ecf9cab24a
1 file changed