udhcpc[6]: fold perform_renew() into its only caller

function                                             old     new   delta
udhcpc_main                                         2550    2541      -9
udhcpc6_main                                        2576    2567      -9
change_listen_mode                                   321     299     -22
.rodata                                           103294  103225     -69
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(add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-109)           Total: -109 bytes

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