Fix corruption after snd_device_name_hint()

Fix corruption after snd_device_name_hint()

snd_device_name_hint() corrupts the config name space after its call.
This results in the error from the suceeding calls of snd_pcm_open()
after snd_device_name_hint().

The bug is in try_config() in namehint.c; it calls snd_config_delete(res)
but res can be two different objects in the function.  One is the object
obtained via snd_config_search_definition(), and another is the one from
snd_config_search_alias_hooks().  The former is the expanded objects,
thus it should be freed.  But, the latter is a reference, and must not be
freed.

This patch adds the check to free or not.

Reported-by: John Lindgren <john.lindgren@tds.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>