remove libbpf_android from libandroid_runtime

since it's not actually ever used at runtime,
it's only meant to be part of the bpfloader boot time one shot binary.

(all non-bpfloader bpf implementation is in .h files only)

Test: TreeHugger, m libandroid_runtime
Bug: 218882781
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I8d3b8ac80ffdbe293221150f7272f7def80fc1c4