Merge branch 'dsa_loop-and-platform_data-cleanups'

Vladimir Oltean says:

====================
dsa_loop and platform_data cleanups

While working to add some new features to dsa_loop, I gathered a number
of cleanup patches. They mostly remove some data structures that became
unused after the multi-switch platforms were migrated to the modern DT
bindings.
====================

Link: https://patch.msgid.link/20260406212158.721806-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>