Packets can be 128 bytes, and are preceded by a prefix byte. So we
need a 129-byte buffer, not a 128-byte buffer.
BUG=chrome-os-partner:30079
BRANCH=none
TEST=do pd software sync; see that 128-byte packets transfer correctly
Change-Id: Ic1e6cfec2c042537768d1cd0eecea509cc90c052
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/210502
Reviewed-by: Alec Berg <alecaberg@chromium.org>