Documentation: nfp: update documentation

The NFP documentation is updated to include information about Corigine,
and the new NFP3800 chips. The 'Acquiring Firmware' section is updated
with new information about where to find firmware.

Two new sections are added to expand the coverage of the documentation.
The new sections include:
- Devlink Info
- Configure Device

Signed-off-by: Walter Heymans <walter.heymans@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20221115090834.738645-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>