Esfi addition (#93)

* Add eSFI discussion

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

* clean up

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

* Convert diagram to drawio

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

* Address some review comments

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

* Final updates to drawing

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

* Update based on review comments

Signed-off-by: Brett Henning <brett.henning@broadcom.com>

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Signed-off-by: Brett Henning <brett.henning@broadcom.com>

Author: bhenning10