Support HID Security Keys with a non-standard report size.

At least one device exists with 60-byte endpoints and previously
Chromium would always assume and write 64-byte reports.

Change-Id: I326e95564a2a0347e007c688c6f0410ff943d745
Reviewed-on: https://chromium-review.googlesource.com/c/1361796
Commit-Queue: Adam Langley <agl@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#614139}
9 files changed