bpf network stats - remove dead code

only the test code ever passes in anything that isn't
a limit {UID_ALL, INTERFACES_ALL, TAG_ALL} (ie. no limit)

Test: TreeHugger, atest libnetworkstats_test FrameworksNetTests
Bug: 276296921
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ida489f25c4da4b12541c6001b41d9e4b30804eff
6 files changed