mb/google/brya/var/marasov: Add DmaProperty for ISH

On Marasov, the ISH is running closed source firmware, so the ChromeOS
security requirements specify it must be behind an IOMMU. Add
DmaProperty to the ISH _DSD on Marasov.

TEST=Kernel marks ISH (PCI device 12.0) as untrusted, and changes the
IOMMU group type to "DMA". Also, device still goes to S0i3.

Before:
$ cat /sys/devices/pci0000\:00/0000\:00\:12.0/untrusted
0

After:
$ cat /sys/devices/pci0000\:00/0000\:00\:12.0/untrusted
1

Change-Id: I4b65b8909c41b06852fe7771375029bd2e76e111
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71263
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/mainboard/google/brya/variants/marasov/overridetree.cb

@@ -206,6 +206,10 @@ chip soc/intel/alderlake
 			probe STORAGE STORAGE_NVME
 		end
 		device ref ish on
+			chip drivers/intel/ish
+				register "add_acpi_dma_property" = "true"
+				device generic 0 on end
+			end
 			probe STORAGE STORAGE_UFS
 		end
 		device ref ufs on