Fix documentation for FSP API.

Fix documentation for FSP API.

The capabilities section is a map, not an array. This CL fixes the example
snippet.

TEST=Testing docs server.
BUG=489217
Committed: https://crrev.com/c90fbc441ef122c1ae71949dfa4ad1bd299c8850
Cr-Commit-Position: refs/heads/master@{#330542}

[mtomasz, 2015-05-19 00:38:49]

mtomasz@chromium.org changed reviewers:
+ kalman@chromium.org

[mtomasz, 2015-05-19 00:38:59]

@kalman: PTAL. Thanks.

[not at google - send to devlin, 2015-05-19 14:33:29]

lgtm

[mtomasz, 2015-05-19 14:44:59]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2015-05-19 14:45:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130943006/1

[commit-bot: I haz the power, 2015-05-19 17:18:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-19 17:19:54]

Patchset 1 (id:??) landed as
https://crrev.com/c90fbc441ef122c1ae71949dfa4ad1bd299c8850
Cr-Commit-Position: refs/heads/master@{#330542}