tools: Sync uapi bpf.h header with latest changes

Synchronize the header after all of the recent changes.
Signed-off-by: NJoe Stringer <joe@cilium.io>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210302171947.2268128-16-joe@cilium.io