Previously, when librte_bpf is built with meson+ninja, its
headers such as bpf_def is not installed to the system.
This commit fixes this problem.
Fixes: 94972f35a02e ("bpf: add BPF loading and execution framework")
Cc: stable@dpdk.org
Signed-off-by: Junxiao Shi <git@mail1.yoursunny.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>