doc: implementers: use callouts
doc: implementers: use callouts

Using callouts relates the diagram to the text much more effectively in
the finished document

Signed-off-by: Mike Holmes <ed44c09f4d7f698f5510adc894a872c73e08c8bd@linaro.org>
Reviewed-and-tested-by: Bill Fischofer <52f3c909d51cc5d355a68a403df6906b3c1a8f83@linaro.org>
Signed-off-by: Mike Holmes <ed44c09f4d7f698f5510adc894a872c73e08c8bd@linaro.org>

mike-holmes-linaro/odp,erachmi/odp,rsalveti/odp,rsalveti/odp,mike-holmes-linaro/odp,ravineet-singh/odp,ravineet-singh/odp,erachmi/odp,rsalveti/odp,erachmi/odp,nmorey/odp,erachmi/odp,nmorey/odp,dkrot/odp,mike-holmes-linaro/odp,ravineet-singh/odp,nmorey/odp,ravineet-singh/odp,mike-holmes-linaro/odp,rsalveti/odp,dkrot/odp,dkrot/odp,nmorey/odp,rsalveti/odp,dkrot/odp