drm/msm/hdmi: Add missing check for alloc_ordered_workqueue

Add check for the return value of alloc_ordered_workqueue as it may return
NULL pointer and cause NULL pointer dereference in `hdmi_hdcp.c` and
`hdmi_hpd.c`.

Fixes: c6a57a50ad ("drm/msm/hdmi: add hdmi hdcp support (V3)")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/517211/
Link: https://lore.kernel.org/r/20230106023011.3985-1-jiasheng@iscas.ac.cn
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/hdmi/hdmi.c

@@ -120,6 +120,10 @@ static int msm_hdmi_init(struct hdmi *hdmi)
 	int ret;
 
 	hdmi->workq = alloc_ordered_workqueue("msm_hdmi", 0);
+	if (!hdmi->workq) {
+		ret = -ENOMEM;
+		goto fail;
+	}
 
 	hdmi->i2c = msm_hdmi_i2c_init(hdmi);
 	if (IS_ERR(hdmi->i2c)) {