[Vxlanmgrd] [CPA] Update the vxlan_tunnel name len to be under IFNAMIZ to overcome netdev creation failure (#2398)

- Why I did
Fixes sonic-net/sonic-buildimage#10466

- How I did it
vxlan_tunnel_name has to be less than IFNAMSIZ ie. (16) for the netdev creation to succeed

Signed-off-by: Vivek Reddy Karri <[email protected]>

Author: vivekrnv

scripts/neighbor_advertiser

@@ -43,7 +43,7 @@ MIRROR_ACL_TABLE_NAME = 'EVERFLOW'
 MIRROR_ACL_TABLEV6_NAME = 'EVERFLOWV6'
 MIRROR_ACL_RULE_NAME = 'rule_arp'
 MIRROR_ACL_RULEV6_NAME = 'rule_nd'
-VXLAN_TUNNEL_NAME = 'neighbor_advertiser'
+VXLAN_TUNNEL_NAME = 'neigh_adv'
 VXLAN_TUNNEL_MAP_PREFIX = 'map_'