ALSA: pcm: Don't embed device

So far we use the embedded struct device for each PCM substreams in
struct snd_pcm.  This may result in UAF when the delayed kobj release
is used; each corresponding struct device is still accessed at the
(delayed) device release, while the snd_pcm object may be already
gone.

As a workaround, detach the struct device from the snd_pcm object by
allocating via the new snd_device_alloc() helper.

A caveat is that we store the PCM substream pointer to drvdata since
the device resume and others require the access to it.

This patch is based on the fix Curtis posted initially.  In this
patch, the changes are split and use the new helper function instead.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jaroslav Kysela <[email protected]>
Signed-off-by: Curtis Malainey <[email protected]>
Tested-by: Curtis Malainey <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

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