perf bpf: Rename bpf_prog_priv__clear() to clear_prog_priv()

perf bpf: Rename bpf_prog_priv__clear() to clear_prog_priv()

The name of bpf_prog_priv__clear() doesn't follow perf's naming
convention. bpf_prog_priv__delete() seems to be a better name. However,
bpf_prog_priv__delete() should be a method of 'struct bpf_prog_priv',
but its first parameter is 'struct bpf_program'.

It is callback from libbpf to clear priv structures when destroying a
bpf program. It is actually a method of bpf_program (libbpf object), but
bpf_program__ functions should be provided by libbpf.

This patch removes the prefix of that function.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1455882283-79592-4-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>