drm: Used DRM_LEGACY for all legacy functions

Except for nouveau, only legacy drivers need this really. And nouveau
is already marked up with DRIVER_KMS_LEGACY_CONTEXT as the special
case.

I've tried to be careful to leave everything related to modeset still
using the DRIVER_MODESET flag. Otherwise it's a direct replacement of
!DRIVER_MODESET with DRIVER_LEGACY checks. Also helps readability
since fewer negative checks overall.

Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Frank Binns <frank.binns@imgtec.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470251470-30830-2-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_fops.c

@@ -92,7 +92,7 @@ static int drm_setup(struct drm_device * dev)
 	int ret;
 
 	if (dev->driver->firstopen &&
-	    !drm_core_check_feature(dev, DRIVER_MODESET)) {
+	    drm_core_check_feature(dev, DRIVER_LEGACY)) {
 		ret = dev->driver->firstopen(dev);
 		if (ret != 0)
 			return ret;
@@ -346,7 +346,7 @@ void drm_lastclose(struct drm_device * dev)
 		dev->driver->lastclose(dev);
 	DRM_DEBUG("driver lastclose completed\n");
 
-	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+	if (drm_core_check_feature(dev, DRIVER_LEGACY))
 		drm_legacy_dev_reinit(dev);
 }
 
@@ -389,7 +389,7 @@ int drm_release(struct inode *inode, struct file *filp)
 		  (long)old_encode_dev(file_priv->minor->kdev->devt),
 		  dev->open_count);
 
-	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+	if (drm_core_check_feature(dev, DRIVER_LEGACY))
 		drm_legacy_lock_release(dev, filp);
 
 	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA))