bpf: KVER_5_8 -> KVER_5_10

Neither 5.8 nor 5.9 are LTS, and thus aren't supported.
Let's simplify to 5.10 which is the actual LTS supported version.

Generated via:
  sed -i -r 's/KVER_5_8/KVER_5_10/' bpf/progs/offload.c
  sed -i -r 's/KVER_5_8/KVER_5_10/' bpf/progs/netd.c
plus manual edit to:
  bpf/headers/include/bpf_helpers.h

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I2b9563e1a392011718d3f7d788f84201993e58c2
3 files changed