drm/msm/dsi: Make TE gpio optional

Platforms containing only DSI video mode devices don't need a TE gpio.
Make TE gpio optional.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index dc4d3e9..9b78432 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1383,7 +1383,8 @@
 		return PTR_ERR(msm_host->disp_en_gpio);
 	}
 
-	msm_host->te_gpio = devm_gpiod_get(panel_device, "disp-te", GPIOD_IN);
+	msm_host->te_gpio = devm_gpiod_get_optional(panel_device, "disp-te",
+								GPIOD_IN);
 	if (IS_ERR(msm_host->te_gpio)) {
 		DBG("cannot get disp-te-gpios %ld", PTR_ERR(msm_host->te_gpio));
 		return PTR_ERR(msm_host->te_gpio);