net: pse-pd: Add PD692x0 PSE controller driver

Add a new driver for the PD692x0 I2C Power Sourcing Equipment controller.
This driver only support i2c communication for now.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240417-feature_poe-v9-12-242293fd1900@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>