perf/arm-cmn: Fix CCLA register offset

perf/arm-cmn: Fix CCLA register offset

Apparently pmu_event_sel is offset by 8 for all CCLA nodes, not just
the CCLA_RNI combination type.

Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support")
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/6e7bb06fef6046f83e7647aad0e5be544139763f.1725296395.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>