pvh_init() sets up the mbi pointer, but leaves mbi_p at 0. This isn't
compatbile with multiboot_fill_boot_info() starting from the physical address,
in order to remove the use of the mbi pointer.
Fixes: 038826b61e85 ("x86/boot: move x86 boot module counting into a new boot_info struct") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.com>