Arch-riscv: Add chosen node

Change-Id: I458665caec08856cd8e61d2cd7a5b0dc5c35d469

src/python/gem5/prebuilt/riscvmatched/riscvmatched_board.py

@@ -348,6 +348,12 @@ class RISCVMatchedBoard(
             )
             root.append(node)
 
+        node = FdtNode(f"chosen")
+        bootargs = self.workload.command_line
+        node.append(FdtPropertyStrings("bootargs", [bootargs]))
+        node.append(FdtPropertyStrings("stdout-path", ["/uart@10000000"]))
+        root.append(node)
+
         # See Documentation/devicetree/bindings/riscv/cpus.txt for details.
         cpus_node = FdtNode("cpus")
         cpus_state = FdtState(addr_cells=1, size_cells=0)
@@ -520,7 +526,7 @@ class RISCVMatchedBoard(
         uart_node.append(
             FdtPropertyWords("interrupt-parent", soc_state.phandle(plic))
         )
-        uart_node.appendCompatible(["ns8250"])
+        uart_node.appendCompatible(["ns8250", "ns16550a"])
         soc_node.append(uart_node)
 
         # VirtIO MMIO disk node