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]