Fix build warning about '-Wimplicit-fallthrough'.
In file included from ./include/linux/acpi.h:15,
from ./include/linux/i2c.h:13,
from sound/soc/codecs/ac108.c:21:
sound/soc/codecs/ac108.c: In function 'ac108_set_fmt':
./include/linux/device.h:1758:5: warning: this statement may fall through [-Wimplicit-fallthrough=]
Change-Id: I89c995e338d2c2afbcc61d49495b406df76e17ab
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>