bpf: introduce BPF_F_XDP_HAS_FRAGS flag in prog_flags loading the ebpf program

Introduce BPF_F_XDP_HAS_FRAGS and the related field in bpf_prog_aux
in order to notify the driver the loaded program support xdp frags.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/db2e8075b7032a356003f407d1b0deb99adaa0ed.1642758637.git.lorenzo@kernel.org


Signed-off-by: Alexei Starovoitov <ast@kernel.org>