riscv: cpu: fu740: Add support for cpu fu740

Add SiFive fu740 cpu to support RISC-V arch

Signed-off-by: Green Wan <green.wan@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/riscv/cpu/fu740/spl.c b/arch/riscv/cpu/fu740/spl.c
new file mode 100644
index 0000000..ea0b228
--- /dev/null
+++ b/arch/riscv/cpu/fu740/spl.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020-201 SiFive, Inc
+ * Pragnesh Patel <pragnesh.patel@sifive.com>
+ */
+
+#include <dm.h>
+#include <log.h>
+
+int spl_soc_init(void)
+{
+	int ret;
+	struct udevice *dev;
+
+	/* DDR init */
+	ret = uclass_get_device(UCLASS_RAM, 0, &dev);
+	if (ret) {
+		debug("DRAM init failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}