This patch introduces bpf.c and bpf.h, which hold common functions
issuing bpf syscall. The goal of these two files is to hide syscall
completely from user. Note that bpf.c and bpf.h deal with kernel
interface only. Things like structure of 'map' section in the ELF object
is not cared by of bpf.[ch].

We first introduce bpf_create_map().

Note that, since functions in bpf.[ch] are wrapper of sys_bpf, they
don't use OO style naming.

Signed-off-by: Wang Nan
Acked-by: Alexei Starovoitov
Cc: Brendan Gregg
Cc: Daniel Borkmann
Cc: David Ahern
Cc: He Kuang
Cc: Jiri Olsa
Cc: Kaixu Xia
Cc: Masami Hiramatsu
Cc: Namhyung Kim
Cc: Peter Zijlstra
Cc: Zefan Li
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1435716878-189507-16-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo