perf arm-spe: Add snapshot mode support

perf arm-spe: Add snapshot mode support

This patch enables support for snapshot mode of arm_spe events,
including the implementation of the necessary callbacks (excluding
find_snapshot, which is to be included in a followup commit).

Reviewed-by: James Clark <james.clark@arm.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: German Gomez <german.gomez@arm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20211109163009.92072-2-german.gomez@arm.com
Tested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>