xen: Add dependency on armv8

U-Boot currently implements hypervisor calls only for ARM64 that's why add
dependency on ARM64. The hardware functionality is also available on
ARMv7a, but currently not supported by U-Boot, hence it is not added to the
list of dependencies here.

Signed-off-by: Michal Simek <michal.simek@amd.com>
1 file changed