virtio netdevice: optimize map_from_guest
virtio netdevice: optimize map_from_guest

Optimize map_from_guest to store the last found element on the
0-th position for faster finding later.

Signed-off-by: Nikolay Nikolaev <5fb6ff14f2a3b931c007d120a649a55e86928f6a@virtualopensystems.com>

alexandergall/snabbswitch,snabbco/snabb,Igalia/snabb,javierguerragiraldez/snabbswitch,snabbco/snabb,wingo/snabb,dpino/snabbswitch,virtualopensystems/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,lukego/snabb,snabbco/snabb,wingo/snabbswitch,andywingo/snabbswitch,lukego/snabb,Igalia/snabbswitch,snabbco/snabb,pirate/snabbswitch,snabbnfv-goodies/snabbswitch,kbara/snabb,eugeneia/snabb,snabbnfv-goodies/snabbswitch,eugeneia/snabb,pavel-odintsov/snabbswitch,snabbco/snabb,plajjan/snabbswitch,hb9cwp/snabbswitch,wingo/snabbswitch,Igalia/snabb,javierguerragiraldez/snabbswitch,wingo/snabbswitch,eugeneia/snabbswitch,dpino/snabb,alexandergall/snabbswitch,aperezdc/snabbswitch,kbara/snabb,kbara/snabb,dwdm/snabbswitch,eugeneia/snabb,fhanik/snabbswitch,pirate/snabbswitch,plajjan/snabbswitch,alexandergall/snabbswitch,snabbnfv-goodies/snabbswitch,eugeneia/snabb,lukego/snabbswitch,lukego/snabbswitch,plajjan/snabbswitch,fhanik/snabbswitch,alexandergall/snabbswitch,eugeneia/snabb,dpino/snabb,mixflowtech/logsensor,heryii/snabb,pavel-odintsov/snabbswitch,Igalia/snabb,dpino/snabbswitch,aperezdc/snabbswitch,wingo/snabb,aperezdc/snabbswitch,Igalia/snabbswitch,hb9cwp/snabbswitch,heryii/snabb,lukego/snabbswitch,eugeneia/snabbswitch,lukego/snabb,dpino/snabb,andywingo/snabbswitch,dpino/snabbswitch,alexandergall/snabbswitch,Igalia/snabbswitch,eugeneia/snabb,Igalia/snabb,kellabyte/snabbswitch,snabbco/snabb,mixflowtech/logsensor,andywingo/snabbswitch,virtualopensystems/snabbswitch,heryii/snabb,lukego/snabb,Igalia/snabb,justincormack/snabbswitch,dpino/snabb,snabbco/snabb,aperezdc/snabbswitch,kbara/snabb,kbara/snabb,eugeneia/snabbswitch,dwdm/snabbswitch,Igalia/snabb,justincormack/snabbswitch,SnabbCo/snabbswitch,andywingo/snabbswitch,kellabyte/snabbswitch,mixflowtech/logsensor,lukego/snabbswitch,mixflowtech/logsensor,wingo/snabb,wingo/snabbswitch,dwdm/snabbswitch,heryii/snabb,xdel/snabbswitch,eugeneia/snabbswitch,wingo/snabb,Igalia/snabbswitch,javierguerragiraldez/snabbswitch,hb9cwp/snabbswitch,mixflowtech/logsensor,SnabbCo/snabbswitch,eugeneia/snabb,Igalia/snabb,heryii/snabb,justincormack/snabbswitch,virtualopensystems/snabbswitch,justincormack/snabbswitch,plajjan/snabbswitch,dpino/snabb,kbara/snabb,wingo/snabb,alexandergall/snabbswitch,kellabyte/snabbswitch,SnabbCo/snabbswitch,heryii/snabb,dpino/snabb,SnabbCo/snabbswitch,fhanik/snabbswitch,snabbco/snabb,alexandergall/snabbswitch,xdel/snabbswitch,Igalia/snabbswitch,xdel/snabbswitch,dpino/snabb,dpino/snabbswitch,hb9cwp/snabbswitch,snabbnfv-goodies/snabbswitch,pavel-odintsov/snabbswitch,eugeneia/snabb,pirate/snabbswitch,wingo/snabb