drm/bridge: ti-sn65dsi83: Make enable GPIO optional

The enable signal may not be controllable by the kernel. Make it
optional.
This is a similar to commit bbda1704 ("drm/bridge: ti-sn65dsi86: Make
enable GPIO optional")
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211213133626.2498056-3-alexander.stein@ew.tq-group.com

drivers/gpu/drm/bridge/ti-sn65dsi83.c

@@ -662,7 +662,8 @@ static int sn65dsi83_probe(struct i2c_client *client,
 	}
 
 	/* Put the chip in reset, pull EN line low, and assure 10ms reset low timing. */
-	ctx->enable_gpio = devm_gpiod_get(ctx->dev, "enable", GPIOD_OUT_LOW);
+	ctx->enable_gpio = devm_gpiod_get_optional(ctx->dev, "enable",
+						   GPIOD_OUT_LOW);
 	if (IS_ERR(ctx->enable_gpio))
 		return PTR_ERR(ctx->enable_gpio);