Read USB device configurations from index 0.
When building the new Windows USB backend I noticed that Windows
rejected requests for the configuration descriptor at index 1. Further
research indicates that while the bConfigurationValue inside a
configuration descriptor starts at 1 the index sent in a GET_DESCRIPTOR
request should start at 0.
The reason this wasn't noticed is that most devices only have one
configuration descriptor and simply don't care what index you ask for.
BUG=None
Review-Url: https://codereview.chromium.org/2689323006
Cr-Commit-Position: refs/heads/master@{#451082}
2 files changed
