iommu/arm-smmu: Warn once when the perfetcher errata patch fails to apply

Default reset value of secure banked register SMMU_sACR.cache_lock is 1.
If it is not been set to 0 by secure software(eg: atf), the non-secure
linux cannot clear ARM_MMU500_ACTLR_CPRE bit. In this situation,
the prefetcher errata is not applied successfully, warn once.

Signed-off-by: Chen Lin <chen45464546@163.com>
Link: https://lore.kernel.org/r/20221103222121.3051-1-chen45464546@163.com


[will: Tweaked wording of diagnostic]
Signed-off-by: Will Deacon <will@kernel.org>