perf: arm_cspmu: Split 64-bit write to 32-bit writes

Split the 64-bit register accesses if 64-bit access is not supported
by the PMU.

Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Reviewed-by: Besar Wicaksono <bwicaksono@nvidia.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230913233941.9814-2-ilkka@os.amperecomputing.com


Signed-off-by: Will Deacon <will@kernel.org>