x86/mb2: avoid Xen image when looking for module/crashkernel position

x86/mb2: avoid Xen image when looking for module/crashkernel position

Commit e22e1c4 (x86/EFI: avoid Xen image when looking for module/kexec
position) added relevant check for EFI case. However, since commit
f75a304 (x86: add multiboot2 protocol support for relocatable images)
Multiboot2 compatible bootloaders are able to relocate Xen image too.
So, we have to avoid also Xen image region in such cases.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>