udhcpc6: add ELAPSED_TIME option to outgoing packets

function                                             old     new   delta
init_d6_packet                                        53     121     +68
udhcpc_main                                         2577    2582      +5
udhcpc6_main                                        2593    2597      +4
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(add/remove: 0/0 grow/shrink: 3/0 up/down: 77/0)               Total: 77 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
3 files changed