drm/i915: Clear DRIVER_ATOMIC on a per-device basis

Currently we're clearing DRIVER_ATOMIC in driver.driver_features
for older platforms. This will not work correctly should we ever
have a system with and old and new GPU in it. While that is not
possible currently let's make the code more correct and use
the per-device driver_features instead.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180913131622.17690-2-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -1336,10 +1336,6 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct drm_i915_private *dev_priv;
 	int ret;
 
-	/* Enable nuclear pageflip on ILK+ */
-	if (!i915_modparams.nuclear_pageflip && match_info->gen < 5)
-		driver.driver_features &= ~DRIVER_ATOMIC;
-
 	ret = -ENOMEM;
 	dev_priv = kzalloc(sizeof(*dev_priv), GFP_KERNEL);
 	if (dev_priv)
@@ -1352,6 +1348,10 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
 	dev_priv->drm.pdev = pdev;
 	dev_priv->drm.dev_private = dev_priv;
 
+	/* Disable nuclear pageflip by default on pre-ILK */
+	if (!i915_modparams.nuclear_pageflip && match_info->gen < 5)
+		dev_priv->drm.driver_features &= ~DRIVER_ATOMIC;
+
 	ret = pci_enable_device(pdev);
 	if (ret)
 		goto out_fini;