Add tether BPF offload config to device config and resource

The tether bpf offload can be enabled by resource config and
device config. The device config has higher priority and it
could override this config which is set by resource config.

Bug: 149997301
Test: -build, flash, boot
      -atest TetheringConfigurationTest
Change-Id: I9c26852d2c926786e141ece6da53df3801c049b2