Add ash/accelerometer/OWNERS

Bug: None
Change-Id: I0235c23d4bb1664d1e701b54dfe196d36cc473db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2521200
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824577}

ash/accelerometer/OWNERS

+xdai@chromium.org