perf/bpf: Allow a BPF program to suppress all sample side effects

Returning zero from a BPF program attached to a perf event already
suppresses any data output. Return early from __perf_event_overflow() in
this case so it will also suppress event_limit accounting, SIGTRAP
generation, and F_ASYNC signalling.

Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240412015019.7060-7-khuey@kylehuey.com