conf.c: snd_config_add: prevent adopting a non-orphan
conf.c: snd_config_add: prevent adopting a non-orphan

When adding a configuration node to another, check that the child node
does not already have a parent.  Otherwise, the old parent's children
list would become corrupted.

Signed-off-by: Clemens Ladisch <9f57ef5ff1095f40b1ee8b7caa363908baef59d7@ladisch.de>

gittup/alsa-lib,mikelima/alsa-lib,zedongchen/alsa-lib,mengdonglin/alsa-lib,mengdonglin/alsa-lib,lgirdwood/alsa-lib,Distrotech/alsa-lib,alsa-project/alsa-lib,Distrotech/alsa-lib,lgirdwood/alsa-lib,Distrotech/alsa-lib,tiwai/alsa-lib,mikelima/alsa-lib,lgirdwood/alsa-lib,gittup/alsa-lib,mikelima/alsa-lib,gittup/alsa-lib,alsa-project/alsa-lib,lgirdwood/alsa-lib,Distrotech/alsa-lib,mengdonglin/alsa-lib,mikelima/alsa-lib,takaswie/alsa-lib,tiwai/alsa-lib,alsa-project/alsa-lib,lgirdwood/alsa-lib,takaswie/alsa-lib,mikelima/alsa-lib,mengdonglin/alsa-lib,zedongchen/alsa-lib,alsa-project/alsa-lib,zedongchen/alsa-lib,takaswie/alsa-lib,zedongchen/alsa-lib,gittup/alsa-lib,takaswie/alsa-lib,zedongchen/alsa-lib,takaswie/alsa-lib,mengdonglin/alsa-lib,tiwai/alsa-lib,Distrotech/alsa-lib,tiwai/alsa-lib