Merge branch 'pse-improve-documentation-clarity'

Kory Maincent says:

====================
PSE: Improve documentation clarity

Thanks to new PSE driver being proposed on the mailinglist figured out
there was some unclear documentation, which lead the developer on the
wrong path. Clarify these documentation.

The changes focus on clarifying the setup_pi_matrix callback behavior
and improving device tree binding descriptions, particularly around
channel-to-PI mapping relationships that are critical for proper PSE
controller integration.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
====================

Link: https://patch.msgid.link/20250620-poe_doc_improve-v1-0-96357bb95d52@bootlin.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>