CRAS: dev_io: change write_streams() return code to unsigned int

1. Fix the return type and the comment of write_streams()
   as it does not return negative int.

2. Remove unused error check of negative return code from
   write_streams().

BUG=b:174213995
TEST=`FEATURES=test USE=asan emerge-${BOARD} adhd`

Change-Id: I80a1888bdcb00f289c507784dcbef1f8b6bdd952
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2703971
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Reviewed-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Tested-by: Judy Hsiao <judyhsiao@chromium.org>
Commit-Queue: Judy Hsiao <judyhsiao@chromium.org>
1 file changed