nat: bump default max translations to 63K
nat: bump default max translations to 63K

Type: improvement

Signed-off-by: Klement Sekera <b8003f27414ca85c37624503b7b4e8f8c829bb4d@cisco.com>
Change-Id: Ibea7ec844d1d910e8a3235e11154b1ecea8302ac

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