perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY

There's no in-tree user anymore.  Let's get rid of it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-3-namhyung@kernel.org