acpi-video-detect: Remove the unused acpi_video_dmi_demote_vendor() function

Remove the now unused acpi_video_dmi_demote_vendor() function, this was
never a proper counter part of acpi_video_dmi_promote_vendor() since
the calls to acpi_video_dmi_promote_vendor() are not counted.
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>

drivers/acpi/video_detect.c

@@ -258,15 +258,6 @@ void acpi_video_dmi_promote_vendor(void)
 }
 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 
-/* To be called when a driver who previously promoted the vendor
- * interface */
-void acpi_video_dmi_demote_vendor(void)
-{
-	acpi_video_caps_check();
-	acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
-}
-EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
-
 /* Returns true if video.ko can do backlight switching */
 int acpi_video_backlight_support(void)
 {

include/linux/acpi.h

@@ -248,7 +248,6 @@ extern bool wmi_has_guid(const char *guid);
 extern long acpi_video_get_capabilities(acpi_handle graphics_dev_handle);
 extern long acpi_is_video_device(acpi_handle handle);
 extern void acpi_video_dmi_promote_vendor(void);
-extern void acpi_video_dmi_demote_vendor(void);
 extern int acpi_video_backlight_support(void);
 extern int acpi_video_display_switch_support(void);
 
@@ -268,10 +267,6 @@ static inline void acpi_video_dmi_promote_vendor(void)
 {
 }
 
-static inline void acpi_video_dmi_demote_vendor(void)
-{
-}
-
 static inline int acpi_video_backlight_support(void)
 {
 	return 0;