datapath/linux: return errors when unable to setup encrypt interface
datapath/linux: return errors when unable to setup encrypt interface

When unable to setup the encryption interface we should error out
prematurely so the user will be aware of the possible errors with the
encryption interface set.

Fixes: f8ca446c07e1 ("cilium: Add option ipv*-pod-subnets to enable chaining + encryption")
Signed-off-by: André Martins <bc9800b9d52a24cce72a73dd528afed53f10e5fc@cilium.io>

tgraf/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium