bpf: add the function header comments
bpf: add the function header comments

Some trivial cleanups also included.

Signed-off-by: Paul Moore <88a1d58bf22a647dce58dd91f9595600dceabba9@redhat.com>

seccomp/libseccomp,amluto/libseccomp,amluto/libseccomp,amluto/libseccomp,seccomp/libseccomp,seccomp/libseccomp