riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree

The D1/D1s SoCs support xtheadvector so it can be included in the
devicetree. Also include vlenb for the cpu.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-3-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi

@@ -27,7 +27,8 @@
 			riscv,isa = "rv64imafdc";
 			riscv,isa-base = "rv64i";
 			riscv,isa-extensions = "i", "m", "a", "f", "d", "c", "zicntr", "zicsr",
-					       "zifencei", "zihpm";
+					       "zifencei", "zihpm", "xtheadvector";
+			thead,vlenb = <128>;
 			#cooling-cells = <2>;
 
 			cpu0_intc: interrupt-controller {