ASoC: pcm: Workaround oops caused by incomplete substream

In soc_pcm_open, substream->private_data can end up being NULL, which
leads to a kernel panic. Probably, this should be caught further up in
the call stack already, but this patch avoids at least the kernel panic.

Issue: SEC-2436
Change-Id: Ifd77abd2e8215a85af9efd8cfea2fd2d1c89dee0
1 file changed