drm/i915/display: Use to_gt() helper for GGTT accesses

GGTT is currently available both through i915->ggtt and gt->ggtt, and we
eventually want to get rid of the i915->ggtt one.
Use to_gt() for all i915->ggtt accesses to help with the future
refactoring.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211219212500.61432-5-andi.shyti@linux.intel.com

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -395,7 +395,7 @@ static void gen7_fbc_activate(struct drm_i915_private *dev_priv)
 			       SNB_CPU_FENCE_ENABLE | params->fence_id);
 		intel_de_write(dev_priv, DPFC_CPU_FENCE_OFFSET,
 			       params->fence_y_offset);
-	} else if (dev_priv->ggtt.num_fences) {
+	} else if (to_gt(dev_priv)->ggtt->num_fences) {
 		intel_de_write(dev_priv, SNB_DPFC_CTL_SA, 0);
 		intel_de_write(dev_priv, DPFC_CPU_FENCE_OFFSET, 0);
 	}

drivers/gpu/drm/i915/display/intel_fbdev.c

@@ -180,7 +180,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	struct drm_device *dev = helper->dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
+	struct i915_ggtt *ggtt = to_gt(dev_priv)->ggtt;
 	const struct i915_ggtt_view view = {
 		.type = I915_GGTT_VIEW_NORMAL,
 	};

drivers/gpu/drm/i915/display/intel_plane_initial.c

@@ -93,7 +93,7 @@ initial_plane_vma(struct drm_i915_private *i915,
 		goto err_obj;
 	}
 
-	vma = i915_vma_instance(obj, &i915->ggtt.vm, NULL);
+	vma = i915_vma_instance(obj, &to_gt(i915)->ggtt->vm, NULL);
 	if (IS_ERR(vma))
 		goto err_obj;