x86/efi: Explicitly include realmode.h to handle RM trampoline quirk

Explicitly include asm/realmode.h, which is needed to handle a real mode
trampoline quirk in efi_free_boot_services(), instead of picking it up
by way of linux/acpi.h.  acpi.h will soon stop including realmode.h so
that changing realmode.h doesn't require a full kernel rebuild.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Link: https://lkml.kernel.org/r/20191126165417.22423-2-sean.j.christopherson@intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>