ALSA: core: set private data for snd_info_entry

Set sound card  as private data for "state" snd info
entry to avoid dereference error when user/userspace
tries to read card state.

Change-Id: Ia165fef682dd420ffedd5352efdf31d96b232a4b
Signed-off-by: Vignesh Kulothungan <vigneshk@codeaurora.org>