Merge branch 'bpf-misc-cleanups'

Alexander Alemayhu says:

====================
Misc BPF cleanup

while looking into making the Makefile in samples/bpf better handle O= I saw
several warnings when running `make clean && make samples/bpf/`. This series
reduces those warnings.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>