drm/panel: boe-th101mb31ig002: switch to devm_gpiod_get_optional() for reset_gpio

Switch the driver to use devm_gpiod_get_optional() on reset_gpio to avoid
driver probe issues when reset line is not specified.
Signed-off-by: Zhaoxiong Lv <lvzhaoxiong@huaqin.corp-partner.google.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240709134754.28013-3-lvzhaoxiong@huaqin.corp-partner.google.comSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240709134754.28013-3-lvzhaoxiong@huaqin.corp-partner.google.com

drivers/gpu/drm/panel/panel-boe-th101mb31ig002-28a.c

@@ -286,7 +286,7 @@ static int boe_th101mb31ig002_dsi_probe(struct mipi_dsi_device *dsi)
 		return dev_err_probe(&dsi->dev, PTR_ERR(ctx->enable),
 				     "Failed to get enable GPIO\n");
 
-	ctx->reset = devm_gpiod_get(&dsi->dev, "reset", GPIOD_OUT_HIGH);
+	ctx->reset = devm_gpiod_get_optional(&dsi->dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(ctx->reset))
 		return dev_err_probe(&dsi->dev, PTR_ERR(ctx->reset),
 				     "Failed to get reset GPIO\n");