staging: drm/imx: fix double free bug in error path

kfree(imx_drm_encoder) is already being called at the label
'err_register'.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/imx-drm/imx-drm-core.c

@@ -584,7 +584,6 @@ int imx_drm_add_encoder(struct drm_encoder *encoder,
 
 	ret = imx_drm_encoder_register(imx_drm_encoder);
 	if (ret) {
-		kfree(imx_drm_encoder);
 		ret = -ENOMEM;
 		goto err_register;
 	}