drm/i915/dsi: don't pretend we support SC GPIOs

False ideas introduced in

commit 1d96a4a
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Fri Mar 18 13:11:10 2016 +0200

    drm/i915/dsi: add support for DSI sequence block v2 gpio element

Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/5264e2f796c4bdc4128cff5a5e245da3038bf1b3.1460039033.git.jani.nikula@intel.com

drivers/gpu/drm/i915/intel_dsi_panel_vbt.c

@@ -209,7 +209,8 @@ static void vlv_exec_gpio(struct drm_i915_private *dev_priv,
 		if (gpio_source == 0) {
 			port = IOSF_PORT_GPIO_NC;
 		} else if (gpio_source == 1) {
-			port = IOSF_PORT_GPIO_SC;
+			DRM_DEBUG_KMS("SC gpio not supported\n");
+			return;
 		} else {
 			DRM_DEBUG_KMS("unknown gpio source %u\n", gpio_source);
 			return;