sound/oss/dmasound: Remove superfluous "break"

Remove superfluous "break", as there is a "return" before them.

Signed-off-by: zuoqilin <zuoqilin@yulong.com>
Link: https://lore.kernel.org/r/20210524070028.45-1-zuoqilin1@163.com


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