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: NSean Christopherson <sean.j.christopherson@intel.com>
Link: https://lkml.kernel.org/r/20191126165417.22423-2-sean.j.christopherson@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/platform/efi/quirks.c

@@ -16,6 +16,7 @@
 #include <asm/efi.h>
 #include <asm/uv/uv.h>
 #include <asm/cpu_device_id.h>
+#include <asm/realmode.h>
 #include <asm/reboot.h>
 
 #define EFI_MIN_RESERVE 5120