Build: Include crypto modules in image when IPsec is enabled

This adds AES, DES, SHA-2 and MD5 modules to the image.

Without these modules, the only built-in algorithm is SHA-1. IPsec
is not usable with only SHA-1 available.
kernel: Enable AEAD cipher modes for 4708 devices

This adds modules for the CCM and GCM modes for use in IPsec.
Because there are quite a few supporting modules required, these
modes are only enabled along with IPsec.

CCM and GCM were introduced in linux version 2.6.24, so they are
only available on ARM devices.
kernel: Enable XCBC MAC algorithm by default

Suggested in RFC 4835 for IPsec
Merge pull request #428 from saintdev/for-upstream

IPsec kernel crypto module additions