fix spelling in comments and strings

The tool comes from https://github.com/jsoref

Signed-off-by: Josh Soref <jsoref@gmail.com>
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>

doc: add graphics to bbdev guide

Add two SVG graphics representing Turbo coding of code blocks
in mbuf data buffer.

Signed-off-by: Amr Mokhtar <amr.mokhtar@intel.com>