perf vendor events arm64 AmpereOneX: Fix frontend_bound calculation

perf vendor events arm64 AmpereOneX: Fix frontend_bound calculation

frontend_bound metrics was miscalculated due to different scaling in
a couple of metrics it depends on. Change the scaling to match with
AmpereOne.

Fixes: 16438b652b46 ("perf vendor events arm64 AmpereOneX: Add core PMU events and metrics")
Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250313201559.11332-3-ilkka@os.amperecomputing.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>