KVM: selftests: aarch64: Update tools copy of arm_pmuv3.h

Now that ARMV8_PMU_PMCR_N is made with GENMASK, update usages to treat
it as a pre-shifted mask.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-9-james.clark@arm.com


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