ucm: Fix uninitialized err in snd_use_case_set()
ucm: Fix uninitialized err in snd_use_case_set()

The compiler warns like:
  main.c:1664:9: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized]

and actually there are slight code paths that slip.
This patch adds the proper initializations to 0 to return the success
code in these code paths.

Signed-off-by: Takashi Iwai <4596b3305151c7ee743192a95d394341e3d3b644@suse.de>

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