acpi-video-detect: Move acpi_is_video_device() to acpi/scan.c

This allows video_detect.c to be build as a module, this is a preparation
patch for the backlight interface selection logic cleanup.

Note this commit also causes acpi_is_video_device() to always be build
indepedent of CONFIG_ACPI_VIDEO, as there is no reason to make its
building depend on CONFIG_ACPI_VIDEO.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 88c92a03..7cb3b0b 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -243,19 +243,15 @@
 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR		0x0400
 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO		0x0800
 
+extern long acpi_is_video_device(acpi_handle handle);
+
 #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)
 
-extern long acpi_is_video_device(acpi_handle handle);
 extern void acpi_video_dmi_promote_vendor(void);
 extern int acpi_video_backlight_support(void);
 
 #else
 
-static inline long acpi_is_video_device(acpi_handle handle)
-{
-	return 0;
-}
-
 static inline void acpi_video_dmi_promote_vendor(void)
 {
 }