ASoC: hdac_hdmi: Fix possible NULL pointer dereference

Pointers hdac_hdmi_pcm and hda_device_id can be NULL, so add check for
valid pointer to avoid NULL pointer dereference.

Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Guneshwor Singh <guneshwor.o.singh@intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/hdac_hdmi.c

@@ -1895,6 +1895,9 @@ static void hdac_hdmi_set_chmap(struct hdac_device *hdac, int pcm_idx,
 	struct hdac_hdmi_pcm *pcm = get_hdmi_pcm_from_id(hdmi, pcm_idx);
 	struct hdac_hdmi_port *port;
 
+	if (!pcm)
+		return;
+
 	if (list_empty(&pcm->port_list))
 		return;
 
@@ -1913,6 +1916,9 @@ static bool is_hdac_hdmi_pcm_attached(struct hdac_device *hdac, int pcm_idx)
 	struct hdac_hdmi_priv *hdmi = edev->private_data;
 	struct hdac_hdmi_pcm *pcm = get_hdmi_pcm_from_id(hdmi, pcm_idx);
 
+	if (!pcm)
+		return false;
+
 	if (list_empty(&pcm->port_list))
 		return false;
 
@@ -1926,6 +1932,9 @@ static int hdac_hdmi_get_spk_alloc(struct hdac_device *hdac, int pcm_idx)
 	struct hdac_hdmi_pcm *pcm = get_hdmi_pcm_from_id(hdmi, pcm_idx);
 	struct hdac_hdmi_port *port;
 
+	if (!pcm)
+		return 0;
+
 	if (list_empty(&pcm->port_list))
 		return 0;
 
@@ -1979,6 +1988,9 @@ static int hdac_hdmi_dev_probe(struct hdac_ext_device *edev)
 	hdmi_priv->chmap.ops.is_pcm_attached = is_hdac_hdmi_pcm_attached;
 	hdmi_priv->chmap.ops.get_spk_alloc = hdac_hdmi_get_spk_alloc;
 
+	if (!hdac_id)
+		return -ENODEV;
+
 	if (hdac_id->driver_data)
 		hdmi_priv->drv_data =
 			(struct hdac_hdmi_drv_data *)hdac_id->driver_data;