vat: fix static analysis warning
vat: fix static analysis warning

replace hand crafted version with existing vector function

Type: fix

Signed-off-by: Andreas Schultz <01ffb76947518f571b4c8b5b33a3c6840779b683@travelping.com>
Change-Id: I94834852469ed316c7bdbd48bb7f479648b2c8e5

FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp