sfc: keep alive neighbour entries while a TC encap action is using them

When processing counter updates, if any action set using the newly
 incremented counter includes an encap action, prod the corresponding
 neighbouring entry to indicate to the neighbour cache that the entry
 is still in use and passing traffic.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://lore.kernel.org/r/20230621121504.17004-1-edward.cree@amd.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>