Merge branch 'lan78xx-phylink-prep'

Oleksij Rempel says:

====================
lan78xx: preparation for PHYLINK conversion

This patch series contains the first part of the LAN78xx driver
refactoring in preparation for converting the driver to use the PHYLINK
framework.

The goal of this initial part is to reduce the size and complexity of
the final PHYLINK conversion by introducing incremental cleanups and
logical separation of concerns, such as:

- Improving error handling in the PHY initialization path
- Refactoring PHY detection and MAC-side configuration
- Moving LED DT configuration to a dedicated helper
- Separating USB link power and flow control setup from the main probe logic
- Extracting PHY interrupt acknowledgment logic

Each patch is self-contained and moves non-PHYLINK-specific logic out of
the way, setting the stage for the actual conversion in a follow-up
patch series.

changes v8 (as split from full v7 00/12 series):
- Split the original series to make review easier
- This part includes only preparation patches; actual PHYLINK
  integration will follow
====================

Signed-off-by: David S. Miller <davem@davemloft.net>