drm/i915: Enable atomic by default on ctg/elk

The watermark code for ctg/elk has been atomic ready for a long time
so let's just flip the switch now that some of the last CxSR issues
have been sorted out (which granted was a problem for vlv/chv as well
despite them already having atomic enabled by default).

v2: Rebase
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221007211108.3883-2-ville.syrjala@linux.intel.comAcked-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_device_info.c

@@ -508,8 +508,9 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
 		runtime->has_dsc = false;
 	}
 
-	/* Disable nuclear pageflip by default on pre-ILK */
-	if (!dev_priv->params.nuclear_pageflip && DISPLAY_VER(dev_priv) < 5)
+	/* Disable nuclear pageflip by default on pre-g4x */
+	if (!dev_priv->params.nuclear_pageflip &&
+	    DISPLAY_VER(dev_priv) < 5 && !IS_G4X(dev_priv))
 		dev_priv->drm.driver_features &= ~DRIVER_ATOMIC;
 }