cut down bpf related privileges

This is driven by 3 things:
  - netd no longer needs setattr, since this is now done by bpfloader
  - nothing should ever unpin maps or programs
  - generic cleanups and additional neverallows

Test: build, atest
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I881cc8bf9fe062aaff709727406c5a51fc363c8e
2 files changed