iommu/arm-smmu: Move Secure access quirk to implementation

Move detection of the Secure access quirk to its new home, trimming it
down in the process - time has proven that boolean DT flags are neither
ideal nor necessarily sufficient, so it's highly unlikely we'll ever add
more, let alone enough to justify the frankly overengineered parsing
machinery.

Change-Id: I86a898715cb1d036949df4dcf7333068bcf64836
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Git-commit: 6d7dff62
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[isaacm@codeaurora.org: resolved merge conflicts]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>