[DPDK] Include AF_XDP PMD in config if required libraries are available

[krsna1729]

Currently we do this to enable AF_XDP.

config makefile patch

This can probably be tackled the same way as mlx/bnx pmds which is cleaner.

We could get rid of this entire dpdk customization block

/cc @ajamshed

[krsna1729]

This is what we did in our side https://github.com/omec-project/upf-epc/pull/67. Shall I send this patch as PR?

@sangjinhan @melvinw @chris3torek