x86/ACPI/sleep: Remove an unnecessary include of asm/realmode.h

None of the declarations in x86's acpi/sleep.h are in any way dependent
on the real mode boot code.  Remove sleep.h's include of asm/realmode.h
to limit the dependencies on realmode.h to code that actually interacts
with the boot code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20191126165417.22423-11-sean.j.christopherson@intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/acpi/sleep.h

@@ -3,7 +3,7 @@
  *	Variables and functions used by the code in sleep.c
  */
 
-#include <asm/realmode.h>
+#include <linux/linkage.h>
 
 extern unsigned long saved_video_mode;
 extern long saved_magic;