add option to enable LLDP MED fast-start and set fast-start timer
Signed-off-by: Stephen Howell <howels@allthatwemight.be>
(cherry picked from commit 24176a6bdd)
Link: https://github.com/openwrt/openwrt/pull/15299
Signed-off-by: Robert Marko <robimarko@gmail.com>