doc: add interface coalesce command POD header.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
doc: add interface driver command POD header.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
doc: add interface offload command POD header.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
doc: add interface pause command POD header.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>