Makefile: Add mechanism for platforms to have multiple builtin DTBs

Currently, we can only include one DTB as builtin for a platform
using FDT_PAYLOAD_DTB make variable in platform config.mk.

This patch adds new mechanism using which we can convert any DTS
file to C source and futher compile-n-link it with libplatsbi.a.

The generated C source will have the DTB contents as an array
"const char <varprefix>_start[]" where <varprefix> is specified
in platform objects.mk makefile.

Example1
--------
If we have built-in k210.dts and desired <varprefix> is
"dt_k210" then specify following in platform objects.mk:
platform-objs-y += k210.o
platform-varprefix-k210.o = dt_k210

Example2
--------
If we have built-in abc/k210.dts and desired <varprefix> is
"dt_abc_k210" then specify following in platform objects.mk:
platform-objs-y += abc/k210.o
platform-varprefix-abc-k210.o = dt_abc_k210

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

scripts/d2c.sh

@@ -0,0 +1,67 @@
+#!/bin/bash
+
+function usage()
+{
+	echo "Usage:"
+	echo " $0 [options]"
+	echo "Options:"
+	echo "     -h                   Display help or usage"
+	echo "     -i <input_file_path> Input binary file path"
+	echo "     -a <c_align>         Output C array alignment"
+	echo "     -p <c_prefix>        Output C array name prefix"
+	exit 1;
+}
+
+# Command line options
+INPUT_PATH=""
+OUTPUT_C_ALIGN=""
+OUTPUT_C_PREFIX=""
+
+while getopts "hi:a:p:o:" o; do
+	case "${o}" in
+	h)
+		usage
+		;;
+	i)
+		INPUT_PATH=${OPTARG}
+		;;
+	a)
+		OUTPUT_C_ALIGN=${OPTARG}
+		;;
+	p)
+		OUTPUT_C_PREFIX=${OPTARG}
+		;;
+	*)
+		usage
+		;;
+	esac
+done
+shift $((OPTIND-1))
+
+if [ -z "${INPUT_PATH}" ]; then
+	echo "Must specify input file path"
+	usage
+fi
+
+if [ ! -f "${INPUT_PATH}" ]; then
+	echo "The input path should be a file"
+	usage
+fi
+
+if [ -z "${OUTPUT_C_ALIGN}" ]; then
+	echo "Must provide output C array alignment"
+	usage
+fi
+
+if [ -z "${OUTPUT_C_PREFIX}" ]; then
+	echo "Must provide output C array name prefix"
+	usage
+fi
+
+printf "const char __attribute__((aligned(%s))) %s_start[] = {\n" "${OUTPUT_C_ALIGN}" "${OUTPUT_C_PREFIX}"
+
+od -v -t x1 -An ${INPUT_PATH} | awk '{for (i=1; i<=NF; i++) printf " 0x%s,", $i; printf "\n"; }'
+
+printf "};\n"
+
+printf "const unsigned long %s_size = sizeof(%s_start);\n" "${OUTPUT_C_PREFIX}" "${OUTPUT_C_PREFIX}"