board: Introduce xenguest_arm64 board

Introduce a minimal Xen guest board running as a virtual
machine under Xen Project's hypervisor [1], [2].

Part of the code is ported from Xen mini-os and also uses
work initially done by different authors from NXP: please see
relevant files for their copyrights.

[1] https://xenbits.xen.org
[2] https://wiki.xenproject.org/

Signed-off-by: Andrii Anisov <andrii_anisov@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
diff --git a/board/xen/xenguest_arm64/Kconfig b/board/xen/xenguest_arm64/Kconfig
new file mode 100644
index 0000000..cc131ed
--- /dev/null
+++ b/board/xen/xenguest_arm64/Kconfig
@@ -0,0 +1,12 @@
+if TARGET_XENGUEST_ARM64
+
+config SYS_BOARD
+	default "xenguest_arm64"
+
+config SYS_VENDOR
+	default "xen"
+
+config SYS_CONFIG_NAME
+	default "xenguest_arm64"
+
+endif