Merge branch 'bpf: Fix strict mode calculation'

Mauricio Vásquez <mauricio@kinvolk.io> says:

====================

This series fixes a bad calculation of strict mode in two places. It
also updates libbpf to make it easier for the users to disable a
specific LIBBPF_STRICT_* flag.

v1 -> v2:
- remove check in libbpf_set_strict_mode()
- split in different commits

v1: https://lore.kernel.org/bpf/20220204220435.301896-1-mauricio@kinvolk.io/
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>