[uboot] create uboot from github:

repo: https://github.com/u-boot/u-boot
	commit: d80bb749fab53da72c4a0e09b8c2d2aaa3103c91

Change-Id: Ie6434426e1ec15bc08bb1832798e371f3fd5fb29

u-boot-2021.10/arch/riscv/lib/sbi_ipi.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#include <common.h>
+#include <asm/encoding.h>
+#include <asm/sbi.h>
+
+int riscv_init_ipi(void)
+{
+	return 0;
+}
+
+int riscv_send_ipi(int hart)
+{
+	ulong mask;
+
+	mask = 1UL << hart;
+	sbi_send_ipi(&mask);
+
+	return 0;
+}
+
+int riscv_clear_ipi(int hart)
+{
+	csr_clear(CSR_SIP, SIP_SSIP);
+
+	return 0;
+}
+
+int riscv_get_ipi(int hart, int *pending)
+{
+	/*
+	 * The SBI does not support reading the IPI status. We always return 0
+	 * to indicate that no IPI is pending.
+	 */
+	*pending = 0;
+
+	return 0;
+}