BPF stable patches

Hi Greg,

if you have a chance, please queue the following BPF patches for -stable:

- up to 4.15.y:

f005afede992 ("trace/bpf: remove helper bpf_perf_prog_read_value from tracepoint type programs")

- up to 4.4.y:

87e0d4f0f37f ("kbuild: disable clang's default use of -fmerge-all-constants") 0fa4fe85f472 ("bpf: skip unnecessary capability check") 6007b080d2e2 ("bpf, x64: increase number of passes")

Thanks, Daniel