drm/edid: abstract override/firmware EDID retrieval

Abstract the debugfs override and the firmware EDID retrieval
function. We'll be needing it in the follow-up. No functional changes.

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Tested-by: Paul Wise <pabs3@bonedaddy.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607110513.12072-1-jani.nikula@intel.com

drivers/gpu/drm/drm_edid.c

@@ -1570,6 +1570,20 @@ static void connector_bad_edid(struct drm_connector *connector,
 	}
 }
 
+/* Get override or firmware EDID */
+static struct edid *drm_get_override_edid(struct drm_connector *connector)
+{
+	struct edid *override = NULL;
+
+	if (connector->override_edid)
+		override = drm_edid_duplicate(connector->edid_blob_ptr->data);
+
+	if (!override)
+		override = drm_load_edid_firmware(connector);
+
+	return IS_ERR(override) ? NULL : override;
+}
+
 /**
  * drm_do_get_edid - get EDID data using a custom EDID block read function
  * @connector: connector we're probing
@@ -1597,15 +1611,10 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 {
 	int i, j = 0, valid_extensions = 0;
 	u8 *edid, *new;
-	struct edid *override = NULL;
-
-	if (connector->override_edid)
-		override = drm_edid_duplicate(connector->edid_blob_ptr->data);
-
-	if (!override)
-		override = drm_load_edid_firmware(connector);
+	struct edid *override;
 
-	if (!IS_ERR_OR_NULL(override))
+	override = drm_get_override_edid(connector);
+	if (override)
 		return override;
 
 	if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)