sfc: add function to atomically update a rule in the MAE
efx_mae_update_rule() changes the action-set-list attached to an MAE
flow rule in the Action Rule Table.
We will use this when neighbouring updates change encap actions.
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com> Signed-off-by: Edward Cree <ecree.xilinx@gmail.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>