riscv: dts: t-head: Add basic device tree for Sipeed Lichee PI 4A board

Only add basic support for CPU, PLIC UART and Timer.

Reviewed-by: Wei Fu <wefu@redhat.com>
Signed-off-by: Yixun Lan <dlan@gentoo.org>
diff --git a/arch/riscv/dts/th1520-lichee-module-4a.dtsi b/arch/riscv/dts/th1520-lichee-module-4a.dtsi
new file mode 100644
index 0000000..dc00e3d
--- /dev/null
+++ b/arch/riscv/dts/th1520-lichee-module-4a.dtsi
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
+ */
+
+/dts-v1/;
+
+#include "th1520.dtsi"
+
+/ {
+	model = "Sipeed Lichee Module 4A";
+	compatible = "sipeed,lichee-module-4a", "thead,th1520";
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x0 0x00000000 0x2 0x00000000>;
+	};
+};
+
+&osc {
+	clock-frequency = <24000000>;
+};
+
+&osc_32k {
+	clock-frequency = <32768>;
+};
+
+&apb_clk {
+	clock-frequency = <62500000>;
+};
+
+&uart_sclk {
+	clock-frequency = <100000000>;
+};