zebra: cosmetic changes for debug

zebra: cosmetic changes for debug

Just remove redundant white spaces in debug information.

Before:
```
2023/01/11 05:04:48 ZEBRA: [W8V7C-6W4DS] init neigh ctx NEIGH_INSTALL: ifp vlan100, mac  9a:68:e9:73:74:88, ip 88.88.88.88
2023/01/11 05:04:48 ZEBRA: [NH6N7-54CD1] Tx RTM_NEWNEIGH family ipv4 IF vlan100(8) Neigh 88.88.88.88 MAC  9a:68:e9:73:74:88 flags 0x10 state 0x40 ext_flags 0x0
```

After:
```
2023/01/11 05:17:26 ZEBRA: [W8V7C-6W4DS] init neigh ctx NEIGH_INSTALL: ifp vlan100, mac 9a:68:e9:73:74:88, ip 88.88.88.88
2023/01/11 05:17:26 ZEBRA: [NH6N7-54CD1] Tx RTM_NEWNEIGH family ipv4 IF vlan100(8) Neigh 88.88.88.88 MAC 9a:68:e9:73:74:88 flags 0x10 state 0x40 ext_flags 0x0
```

Signed-off-by: anlan_cs <vic.lan@pica8.com>