Doc.../sound/soc/platform.rst: snd_soc_platform_driver out of sync

[Andrey Utkin]

Hi maintainers of Sound and/or Docs.

Documentation/sound/soc/platform.rst quotes outdated definition of
"struct snd_soc_platform_driver". I spotted this because it shows like
there are suspend/resume function pointers while this is no longer true.

I don't have a good idea how to update the doc, I am just sure that mere
update of the struct definition is not the way to go.

Hope this report helps.
Thanks for you work!