mixer: change code formatting for elem_write_enum()
mixer: change code formatting for elem_write_enum()

This commit applies code format according to typical and moderate rule.

Signed-off-by: Takashi Sakamoto <d5ec7d0cd8074757a1f5eb708bc105c3065a65ea@sakamocchi.jp>
Signed-off-by: Takashi Iwai <4596b3305151c7ee743192a95d394341e3d3b644@suse.de>

alsa-project/alsa-lib,tiwai/alsa-lib,zedongchen/alsa-lib,tiwai/alsa-lib,takaswie/alsa-lib,takaswie/alsa-lib,alsa-project/alsa-lib,alsa-project/alsa-lib,takaswie/alsa-lib,zedongchen/alsa-lib,takaswie/alsa-lib,takaswie/alsa-lib,alsa-project/alsa-lib,zedongchen/alsa-lib,zedongchen/alsa-lib,zedongchen/alsa-lib,tiwai/alsa-lib,tiwai/alsa-lib