drm/crtc: Fix edid length computation

The length of each EDID block is EDID_LENGTH, and number of blocks is
(1 + edid->extensions) - we need to multiply not add them.

This causes wrong EDID to be passed on, and is a regression introduced
by d2ed343 (drm: Introduce helper for replacing blob properties)

Signed-off-by: Shixin Zeng <zeng.shixin@gmail.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
[danvet: Add Cc: and fix commit summary.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc.c

@@ -4732,7 +4732,7 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
 		return 0;
 
 	if (edid)
-		size = EDID_LENGTH + (1 + edid->extensions);
+		size = EDID_LENGTH * (1 + edid->extensions);
 
 	ret = drm_property_replace_global_blob(dev,
 					       &connector->edid_blob_ptr,