helper: iplookuptable: avoid potential null pointer dereferences
helper: iplookuptable: avoid potential null pointer dereferences

Resolve Bug 2862 by checking pointer validity before dereferencing.
https://bugs.linaro.org/show_bug.cgi?id=2862

Signed-off-by: Bill Fischofer <52f3c909d51cc5d355a68a403df6906b3c1a8f83@linaro.org>
Reviewed-by: Mike Holmes <ed44c09f4d7f698f5510adc894a872c73e08c8bd@linaro.org>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

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