kernel: net: pse-pd: backport PSE v6.13-v6.19

kernel: net: pse-pd: backport PSE v6.13-v6.19

Backport the PSE-PD (Power Sourcing Equipment - Powered Device)
framework updates from Linux 6.13 through 6.19. This brings modern
PoE (Power over Ethernet) controller support to OpenWrt, enabling
userspace control of PSE hardware via ethtool.

Key features:
- Enhanced ethtool integration for PSE status and configuration
- Power domain support with budget evaluation strategies
- PSE event reporting via netlink
- Port priority management for power budget allocation
- New Si3474 PSE controller driver

Backported commits:

v6.13 core framework and TPS23881 improvements:
- 6e56a6d47a7f net: pse-pd: Add power limit check
- 0b567519d115 net: pse-pd: tps23881: Simplify function returns
- 4c2bab507eb7 net: pse-pd: tps23881: Use helpers to calculate bit offset
- f3cb3c7bea0c net: pse-pd: tps23881: Add missing configuration register
- 3e9dbfec4998 net: pse-pd: Split ethtool_get_status
  into multiple callbacks
- 4640a1f0d8f2 net: pse-pd: Remove is_enabled callback from drivers
- 7f076ce3f173 net: pse-pd: tps23881: Add power limit
  and measurement features
- 10276f3e1c7e net: pse-pd: Fix missing PI of_node description
- 5385f1e1923c net: pse-pd: Clean ethtool header of PSE structures

v6.17 power domains and event support:
- fa2f0454174c net: pse-pd: Introduce attached_phydev to pse control
- fc0e6db30941 net: pse-pd: Add support for reporting events
- f5e7aecaa4ef net: pse-pd: tps23881: Add support for PSE events
- 50f8b341d268 net: pse-pd: Add support for PSE power domains
- 1176978ed851 net: ethtool: Add support for power domains index
- c394e757dedd net: pse-pd: Add helper to report hw enable status
- ffef61d6d273 net: pse-pd: Add support for budget evaluation strategies
- 359754013e6a net: pse-pd: pd692x0: Add PSE PI priority feature
- 24a4e3a05dd0 net: pse-pd: pd692x0: Add controller and manager power
- 56cfc97635e9 net: pse-pd: tps23881: Add static port priority feature
- d12b3dc10609 net: pse-pd: pd692x0: reduce stack usage

v6.18 Si3474 driver and fixes:
- 1c67f9c54cdc net: pse-pd: pd692x0: Fix power budget leak
- 7ef353879f71 net: pse-pd: pd692x0: Skip power budget when undefined
- a2317231df4b net: pse-pd: Add Si3474 PSE controller driver

v6.19 maintenance and TPS23881B support:
- 2c95a756e0cf net: pse-pd: tps23881: Fix current measurement scaling
- f197902cd21a net: pse-pd: pd692x0: Replace __free macro
- 6fa1f8b64a47 net: pse-pd: pd692x0: Separate configuration parsing
- 8f3d044b34fe net: pse-pd: pd692x0: Preserve PSE configuration
- 4d07797faaa1 net: pse-pd: tps23881: Add support for TPS23881B

Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
Link: https://github.com/openwrt/openwrt/pull/21810
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>