perf bpf-loader: Remove unecessary includes from bpf-loader.h

perf bpf-loader: Remove unecessary includes from bpf-loader.h

To cut the header dep tree, to get unecessary object rebuilds to be
reduced when a change happens in headers.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-ph72xhl9moqa0g1hxcyudwfn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>