[U-Boot] [PATCH 02/26] binman: Add docs explaining how to enable binman for a board

[sjg at google.com]

The process is not obvious. Add a little section to explain how to move a
board to use binman.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 tools/binman/README | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

Applied to u-boot-dm thanks!