drm/i915/dsi: Fix NULL pointer deref in vlv_dphy_param_init()

Commit 77ba0b8 ("drm/i915/dsi: convert vlv_dsi.[ch] to struct
intel_display") added a to_intel_display(connector) call to
vlv_dphy_param_init() but when vlv_dphy_param_init() gets called
the connector object has not been initialized yet, so this leads
to a NULL pointer deref:

 BUG: kernel NULL pointer dereference, address: 000000000000000c
 ...
 Hardware name: ASUSTeK COMPUTER INC. T100TA/T100TA, BIOS T100TA.314 08/13/2015
 RIP: 0010:vlv_dsi_init+0x4e6/0x1600 [i915]
 ...
 Call Trace:
  <TASK>
  ? intel_step_name+0x4be8/0x5c30 [i915]
  intel_setup_outputs+0x2d6/0xbd0 [i915]
  intel_display_driver_probe_nogem+0x13f/0x220 [i915]
  i915_driver_probe+0x3d9/0xaf0 [i915]

Use to_intel_display(&intel_dsi->base) instead to fix this.

Fixes: 77ba0b8 ("drm/i915/dsi: convert vlv_dsi.[ch] to struct intel_display")
Signed-off-by: Hans de Goede <[email protected]>
Reviewed-by: Jani Nikula <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jani Nikula <[email protected]>
(cherry picked from commit 0dc6bfb50a5d0759e726cd36a3d3b7529fd2a627)
Signed-off-by: Joonas Lahtinen <[email protected]>

Author: Hans de Goede

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

@@ -1589,8 +1589,8 @@ static void vlv_dsi_add_properties(struct intel_connector *connector)
 
 static void vlv_dphy_param_init(struct intel_dsi *intel_dsi)
 {
+	struct intel_display *display = to_intel_display(&intel_dsi->base);
 	struct intel_connector *connector = intel_dsi->attached_connector;
-	struct intel_display *display = to_intel_display(connector);
 	struct mipi_config *mipi_config = connector->panel.vbt.dsi.config;
 	u32 tlpx_ns, extra_byte_count, tlpx_ui;
 	u32 ui_num, ui_den;