perf report: Add parallelism filter

perf report: Add parallelism filter

Add parallelism filter that can be used to look at specific parallelism
levels only. The format is the same as cpu lists. For example:

Only single-threaded samples: --parallelism=1
Low parallelism only: --parallelism=1-4
High parallelism only: --parallelism=64-128

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: https://lore.kernel.org/r/e61348985ff0a6a14b07c39e880edbd60a8f8635.1739437531.git.dvyukov@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>