doc: release: mention default-speeds dt prop

mention default-speeds dt prop

Signed-off-by: Fin Maaß <[email protected]>

Author: maass-hamburg

doc/releases/migration-guide-4.3.rst

@@ -159,6 +159,12 @@ Ethernet
   register at run-time, making the devicetree property ``amba-ahb-dbus-width`` obsolete, which
   has therefore been removed.
 
+* The :dtcompatible:`nxp,enet-mac` and :dtcompatible:`xlnx,gem` drivers are no longer configuring
+  the link speed and duplex mode of the phy via  :c:func:`phy_configure_link` during initialization.
+  Instead, the user has to use the ``default-speeds`` devicetree property of the phy, if they want
+  to restrict the advertised speeds for auto-negotiation, when the mac only supports a subset of the
+  phy supported speeds. (:github:`91572`)
+
 MFD
 ===
 

doc/releases/release-notes-4.3.rst

@@ -229,6 +229,11 @@ New APIs and options
     * :kconfig:option:`CONFIG_SDL_DISPLAY_DEFAULT_PIXEL_FORMAT_AL_88`
     * :kconfig:option:`CONFIG_SDL_DISPLAY_COLOR_TINT`
 
+* Ethernet
+
+   * The devicetree property ``default-speeds`` was added to most of the ethernet phys to configure
+     the advertised speeds for auto-negotiation during initialization of the driver.
+
 * Haptics
 
   * :kconfig:option:`CONFIG_HAPTICS_SHELL`