[PATCH] drm: xlnx: zynqmp_dpsub: Add NULL checks in zynqmp_audio_init()

[Markus Elfring]

> devm_kasprintf() can return a NULL pointer on failure,but this
> returned value in zynqmp_audio_init() is not checked.

Another wording suggestion:
devm_kasprintf() calls can return null pointers on failure.
But some return values were not checked in zynqmp_audio_init().


> Add NULL check in zynqmp_audio_init(), to handle kernel NULL
> pointer dereference error.

Thus add three checks to prevent null pointer dereferences.

Regards,
Markus