merge Tether{Down,Up}stream4{Key,Value}

The keys are identical, and the values nearly so, this will make everyone's life easier.

Test: atest, TreeHugger, git grep 'Tether(Down|Up)stream4(Key|Value)' finds nothing
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Id4c9db8d8a53baf445eb9e0899c96507518f5796
2 files changed