ASoC: SOF: Intel: hda: Fix NULL pointer dereference

In the Linux kernel, the following vulnerability has been resolved: ASoC: SOF: Intel: hda: Fix NULL pointer dereference If there's a mismatch between the DAI links in the machine driver and the topology, it is possible that the playback/capture widget is not set, especially in the case of loopback capture for echo reference where we use the dummy DAI link. Return the error when the widget is not set to avoid a null pointer dereference like below when the topology is broken. RIP: 0010:hda_dai_get_ops.isra.0+0x14/0xa0 [snd_sof_intel_hda_common]