[TF-A] ATF LTS version

Hello team,

To extend the discussion around version upgrades from our last call, I would like to understand if there is enough interest around generating a LTS version of the TF-A to alleviate the pain.

For NVIDIA, this would be helpful as it streamlines the upgrade path for our devices in the field. The LTS version will guarantee security fixes, bug fixes, stability fixes for the longer term and we won't have to upgrade the entire firmware to get these goodies.

It would be interesting to see what OEMs and maintainers think about this? Has this been discussed at tf.org or Arm internally?

-Varun