ACPI: property: Silence missing-declarations warning in apple.c

Silence an annoying message emitted for W=1 builds:

drivers/acpi/x86/apple.c:30:6: warning: no previous declaration for 'acpi_extract_apple_properties' [-Wmissing-declarations]
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/x86/apple.c

@@ -8,6 +8,7 @@
 #include <linux/bitmap.h>
 #include <linux/platform_data/x86/apple.h>
 #include <linux/uuid.h>
+#include "../internal.h"
 
 /* Apple _DSM device properties GUID */
 static const guid_t apple_prp_guid =