Merge branch 'bpf-selftest-endianess-fixes'

Ilya Leoshkevich says:

====================
Patch 1 is a preparatory commit, which introduces 64-bit endianness
conversion functions.

Patch 2 fixes reading the wrong byte of an int.

Patch 3 improves error reporting.

Patch 4 uses the new conversion functions to fix wrong endianness of
immediates.

v1->v2: Use bpf_ntohl and bpf_be64_to_cpu, drop __bpf_le64_to_cpu.
v2->v3: Split bpf_be64_to_cpu introduction into a separate patch.
        Use the new functions in test_lwt_seg6local.c and
	test_seg6_loop.c.
v3->v4: Improved commit message, split fixes that are not related to
        each other into separate patches.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>