ANDROID: iommu/io-pgtable-arm: Add IOMMU_SYS_CACHE/_NWA

Add IOMMU_SYS_CACHE and IOMMU_SYS_CACHE_NWA for device mappings.
IOMMU_SYS_CACHE, used by itself, allows device accesses to be cached
in the system cache (if present). IOMMU_SYS_CACHE_NWA, used by itself,
allows device accesses to be cached in the system cache with a
no-write allocate policy.

On systems in which devices can also snoop the CPU caches (i.e.
IO-coherency is present), IOMMU_SYS_CACHE_NWA and IOMMU_SYS_CACHE can
be combined with IOMMU_CACHE (with IOMMU_SYS_CACHE + IOMMU_CACHE being
a no-op).

Bug: 189339242
Change-Id: Ic91616a148f39fead008a5b87a54ffd781fee734
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
Signed-off-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com>