drm: rip out drm_platform_exit

This very much looks like a remnant of the old legady ums shadow
attach days. Now with the last users gone we can rip it out since
we won't ever support an ums drm driver again.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_platform.c

@@ -151,14 +151,3 @@ int drm_platform_init(struct drm_driver *driver, struct platform_device *platfor
 	return drm_get_platform_dev(platform_device, driver);
 }
 EXPORT_SYMBOL(drm_platform_init);
-
-void drm_platform_exit(struct drm_driver *driver, struct platform_device *platform_device)
-{
-	struct drm_device *dev, *tmp;
-	DRM_DEBUG("\n");
-
-	list_for_each_entry_safe(dev, tmp, &driver->device_list, driver_item)
-		drm_put_dev(dev);
-	DRM_INFO("Module unloaded\n");
-}
-EXPORT_SYMBOL(drm_platform_exit);

include/drm/drmP.h

@@ -1701,7 +1701,6 @@ extern int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *speed_mask);
 
 /* platform section */
 extern int drm_platform_init(struct drm_driver *driver, struct platform_device *platform_device);
-extern void drm_platform_exit(struct drm_driver *driver, struct platform_device *platform_device);
 
 /* returns true if currently okay to sleep */
 static __inline__ bool drm_can_sleep(void)