perf vendor events arm64: Fix JSON indentation to 4 spaces standard

Correct indentation to 4 spaces, same as the other JSON files.

Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Andrew Kilroy <andrew.kilroy@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20211203123525.31127-2-andrew.kilroy@arm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>