platform: Add support for Shakti C-class SoC from IIT-M

C-Class is a member of the SHAKTI family of processors from Indian
Institute of Technology - Madras(IIT-M).
It is an extremely configurable and commercial-grade 5-stage in-order
core supporting the standard RV64GCSUN ISA extensions.

https://gitlab.com/shaktiproject/cores/c-class/blob/master/README.md

We add OpenSBI support for Shakti C-class SoC.

Signed-off-by: Vijai Kumar K <vijai@behindbytes.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

lib/utils/serial/fdt_serial_shakti.c

@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Vijai Kumar K <vijai@behindbytes.com>
+ *
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+#include <sbi_utils/serial/shakti-uart.h>
+
+static int serial_shakti_init(void *fdt, int nodeoff,
+				const struct fdt_match *match)
+{
+	int rc;
+	struct platform_uart_data uart;
+
+	rc = fdt_parse_shakti_uart_node(fdt, nodeoff, &uart);
+	if (rc)
+		return rc;
+
+	return shakti_uart_init(uart.addr, uart.freq, uart.baud);
+}
+
+static const struct fdt_match serial_shakti_match[] = {
+	{ .compatible = "shakti,uart0" },
+	{ },
+};
+
+struct fdt_serial fdt_serial_shakti = {
+	.match_table = serial_shakti_match,
+	.init = serial_shakti_init,
+	.getc = shakti_uart_getc,
+	.putc = shakti_uart_putc
+};