perf/arm_cspmu: Move register definitons to header

Implementations may occasionally want to refer to register offsets, so
for the sake of consistency move all of the register definitions to join
the PMIIDR fields in the private header where they can be shared. As an
example nicety, we can then define Ampere's imp-def filters in terms of
the architectural PMIMPDEF range rather than open-coded offsets.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/5a3c796560665b51cb63fec0d473afd8f8d0a836.1741190362.git.robin.murphy@arm.com


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