Merge branch 'net-dsa-mv88e6xxx-remove-some-6250-specific-methods'

Rasmus Villemoes says:

====================
net: dsa: mv88e6xxx: remove some 6250-specific methods

v2:
 - resend now that the bug-fix patch (87fe04367d84, "net: dsa:
   mv88e6xxx: also read STU state in mv88e6250_g1_vtu_getnext") is in
   net and also merged to net-next.
 - include various tags in patch 1.
 - add second similar patch for loadpurge.
====================

Link: https://lore.kernel.org/r/20210125150449.115032-1-rasmus.villemoes@prevas.dk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>