dev-arm: Fix SMMUv3 16KB next-level table address masking

dev-arm: Fix SMMUv3 16KB next-level table address masking

The next-level table address for a granule size of 16KB is retrieved
from the 47:14 bits of the current table descriptor (instead of
47:12, which is the valid masking for a 4KB granule)

Change-Id: I570138a34003dc034d8e67dc1209316157d57205
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Michiel van Tol <michiel.vantol@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23763
Tested-by: kokoro <noreply+kokoro@google.com>