drm/i915/dsi: Use enc_to_intel_dsi()

Use enc_to_intel_dsi() instead hand rolling it.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240307151810.24208-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -1616,8 +1616,7 @@ static int gen11_dsi_compute_config(struct intel_encoder *encoder,
 				    struct drm_connector_state *conn_state)
 {
 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
-	struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
-						   base);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
 	struct intel_connector *intel_connector = intel_dsi->attached_connector;
 	struct drm_display_mode *adjusted_mode =
 		&pipe_config->hw.adjusted_mode;

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

@@ -273,8 +273,7 @@ static int intel_dsi_compute_config(struct intel_encoder *encoder,
 				    struct drm_connector_state *conn_state)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
-						   base);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
 	struct intel_connector *intel_connector = intel_dsi->attached_connector;
 	struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
 	int ret;