x86/power/64: Use __pa() for physical address computation

The value of temp_level4_pgt is the physical address of the
top-level page directory, so use __pa() to compute it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

arch/x86/power/hibernate_64.c

@@ -113,7 +113,7 @@ static int set_up_temporary_mappings(void)
 			return result;
 	}
 
-	temp_level4_pgt = (unsigned long)pgd - __PAGE_OFFSET;
+	temp_level4_pgt = __pa(pgd);
 	return 0;
 }