Remove iterator typedefs for USB descriptor types.

Remove iterator typedefs for USB descriptor types.

C++11 range-based for loops make it a lot easier to iterate over an STL
container without incredibly long type names. The last users of these
typedefs have been updated and so they are no longer necessary.

BUG=

Committed: https://crrev.com/61aa5180a1fbbd40722d96433b3fb2ca5a328ee1
Cr-Commit-Position: refs/heads/master@{#312949}

[Reilly Grant (use Gerrit), 2015-01-23 21:37:27]

reillyg@chromium.org changed reviewers:
+ scheib@chromium.org

[Reilly Grant (use Gerrit), 2015-01-23 21:38:01]

Vince, please take a look at this trivial patch to remove some unused typedefs.

[scheib, 2015-01-23 22:16:37]

The CQ bit was checked by scheib@chromium.org

[scheib, 2015-01-23 22:16:38]

lgtm

[commit-bot: I haz the power, 2015-01-23 22:18:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869063004/1

[commit-bot: I haz the power, 2015-01-23 22:27:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-23 22:28:27]

Patchset 1 (id:??) landed as
https://crrev.com/61aa5180a1fbbd40722d96433b3fb2ca5a328ee1
Cr-Commit-Position: refs/heads/master@{#312949}