xen: Add essential and required interface headers

Add essential and required Xen interface headers only taken from
the stable Linux kernel stable/linux-5.7.y at commit
66dfe4522160 Linux 5.7.5.

These are better suited for U-boot than the original headers
from Xen as they are the stripped versions of the same.

At the same time use public protocols from Xen RELEASE-4.13.1, at
commit 6278553325a9 update Xen version to 4.13.1
as those have more comments in them.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Acked-by: Peng Fan <peng.fan@nxp.com>

include/xen/interface/io/protocols.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * protocols.h
+ *
+ * Copyright (c) 2008, Keir Fraser
+ *
+ * Xen protocols, which are used as ABI rules governing the format of all
+ * ring request and response structures.
+ */
+
+#ifndef __XEN_PROTOCOLS_H__
+#define __XEN_PROTOCOLS_H__
+
+#define XEN_IO_PROTO_ABI_X86_32     "x86_32-abi"
+#define XEN_IO_PROTO_ABI_X86_64     "x86_64-abi"
+#define XEN_IO_PROTO_ABI_ARM        "arm-abi"
+
+#if defined(__i386__)
+# define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_X86_32
+#elif defined(__x86_64__)
+# define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_X86_64
+#elif defined(__arm__) || defined(__aarch64__)
+# define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_ARM
+#else
+# error arch fixup needed here
+#endif
+
+#endif