vhost-user: fix crash in vhost_user_intfc_tx (VPP-519)
vhost-user: fix crash in vhost_user_intfc_tx (VPP-519)

The crash was the result of indexing off the end of the next[] array.
Removing that prefetch code completelly, as it is questionable
how much it helps so late in the game.

Change-Id: I7bc83483a1088437edb4ac0f95a54c39afce136b
Signed-off-by: Damjan Marion <9141bba8b2efed526e55cf796d48631af330ad98@cisco.com>

FDio/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,chrisy/vpp,chrisy/vpp,milanlenco/vpp,milanlenco/vpp,FDio/vpp,chrisy/vpp,milanlenco/vpp,milanlenco/vpp,GabrielGanne/vpp-flowtable,GabrielGanne/vpp-flowtable,chrisy/vpp,vpp-dev/vpp,milanlenco/vpp,GabrielGanne/vpp-flowtable,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,milanlenco/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp