drm/i915/display/vlv_dsi: Prefer drm_WARN_ON over WARN_ON

struct drm_device specific drm_WARN* macros include device information
in the backtrace, so we know what device the warnings originate from.

Prefer drm_WARN_ON over WARN_ON.
Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200406112800.23762-14-pankaj.laxminarayan.bharadiya@intel.com

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

@@ -864,7 +864,7 @@ static void bxt_dsi_enable(struct intel_atomic_state *state,
 			   const struct intel_crtc_state *crtc_state,
 			   const struct drm_connector_state *conn_state)
 {
-	WARN_ON(crtc_state->has_pch_encoder);
+	drm_WARN_ON(state->base.dev, crtc_state->has_pch_encoder);
 
 	intel_crtc_vblank_on(crtc_state);
 }