example: ipsec: fix copy/paste error in README
example: ipsec: fix copy/paste error in README

Instructions should include adding static ARP entry as per the
instructions for the other end of the tunnel on line #138.

Signed-off-by: Stuart Haslam <1fce01f364ef5298e64e07a42e08efeef153fa98@linaro.org>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

kalray/odp-mppa,rsalveti/odp,mike-holmes-linaro/odp,nmorey/odp,kalray/odp-mppa,dkrot/odp,erachmi/odp,dkrot/odp,kalray/odp-mppa,ravineet-singh/odp,rsalveti/odp,mike-holmes-linaro/odp,ravineet-singh/odp,rsalveti/odp,kalray/odp-mppa,rsalveti/odp,mike-holmes-linaro/odp,rsalveti/odp,nmorey/odp,dkrot/odp,ravineet-singh/odp,nmorey/odp,erachmi/odp,mike-holmes-linaro/odp,dkrot/odp,kalray/odp-mppa,erachmi/odp,erachmi/odp,kalray/odp-mppa,ravineet-singh/odp,nmorey/odp,kalray/odp-mppa