devtools: test nfb and AF_XDP build with make

devtools: test nfb and AF_XDP build with make

The nfb PMD is disabled by default because of its dependency
on netcope-common package.
The variable DPDK_DEP_NFB was introduced but not used to notify
the dependency availability in the build test script.

The AF_XDP PMD is disabled by default because of its dependency
on libbpf on Linux.
An option was missing to notify the dependency availability
in the build test script.

Fixes: 6435f9a0ac22 ("net/nfb: add new netcope driver")
Fixes: f1debd77efaf ("net/af_xdp: introduce AF_XDP PMD")
Cc: stable@dpdk.org
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>