perf/core: Add perf_sample_save_raw_data() helper

When we save the raw_data to the perf sample data, we need to update
the sample flags and the dynamic size.  To make sure this is done
consistently, add the perf_sample_save_raw_data() helper and convert
all call sites.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230118060559.615653-4-namhyung@kernel.org