tcp: optimize tcp input
tcp: optimize tcp input

Change-Id: Ib98cfc93f6c574de5250f251925f7ed4e86f5f6f
Signed-off-by: Florin Coras <c9715e5cdf0718c2e9b10678757dfb027875eba2@cisco.com>

chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp