staging: r8188eu: remove action_handler string

Remove the unused str component from struct action_handler and the
corresponding entries in OnAction_tbl.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220502200652.143665-5-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>