add more precise bpf levels

This is to allow fixing a broken OffloadUtils netd test, but this will
also be useful for future support to make programs per kernel version.

We make the string versions of the enum more readable, because there
is exactly one user:

adb shell dumpsys netd | egrep -i bpf
  BPF module status: enabled
  BPF support level: Extended [4.14]
  ...

Test: build, atest
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I843bd7355703a78acc8343ca7f647ce9366927eb

0 files changed, 0 insertions, 0 deletions