Merge branch 'add-si3474-pse-controller-driver'

Piotr Kubik says:

====================
Add Si3474 PSE controller driver

From: Piotr Kubik <piotr.kubik@adtran.com>

These patch series provide support for Skyworks Si3474 I2C Power
Sourcing Equipment controller.

Based on the TPS23881 driver code.

Supported features of Si3474:
- get port status,
- get port power,
- get port voltage,
- enable/disable port power

Signed-off-by: Piotr Kubik <piotr.kubik@adtran.com>
====================

Link: https://patch.msgid.link/6af537dc-8a52-4710-8a18-dcfbb911cf23@adtran.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>