From the dhcp daemon log, we can see that dhcp will fail to acquire
the lease when the link is down, and success on retry.
```
2024/08/21 21:30:44 macvlan-dhcp/eth1: acquiring lease
2024/08/21 21:30:44 Link "eth1" down. Attempting to set up
2024/08/21 21:30:44 network is down
2024/08/21 21:30:44 retrying in 2.641696 seconds
2024/08/21 21:30:49 macvlan-dhcp/eth1: lease acquired, expiration is 2024-08-22 09:30:49.755367962 +0800 CST m=+43205.712107889
```
After move the code of set up link to the beginning of the function, the
dhcp success on first time.
```
2024/08/21 22:04:02 macvlan-dhcp/eth1: acquiring lease
2024/08/21 22:04:02 Link "eth1" down. Attempting to set up
2024/08/21 22:04:05 macvlan-dhcp/eth1: lease acquired, expiration is 2024-08-22 10:04:05.297887726 +0800 CST m=+43203.081141304
```
Signed-off-by: Songmin Li <lisongmin@protonmail.com>
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