dt: amd-seattle: add a description of the PCIe SMMU

Add a description of the SMMU that covers the PCIe host bridge
on AMD Seattle.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: ardbiesheuvel

arch/arm64/boot/dts/amd/amd-seattle-soc.dtsi

@@ -239,6 +239,16 @@
 				<0x02000000 0x00 0x40000000 0x00 0x40000000 0x00 0x80000000>,
 				/* 64-bit MMIO (size= 508G) */
 				<0x03000000 0x01 0x00000000 0x01 0x00000000 0x7f 0x00000000>;
+			iommu-map = <0x0 &pcie_smmu 0x0 0x10000>;
+		};
+
+		pcie_smmu: iommu@e0a00000 {
+			compatible = "arm,mmu-401";
+			reg = <0 0xe0a00000 0 0x10000>;
+			#global-interrupts = <1>;
+			interrupts = <0 333 4>, <0 333 4>;
+			#iommu-cells = <1>;
+			dma-coherent;
 		};
 
 		/* Perf CCN504 PMU */