[fuchsia] Update header include
[fuchsia] Update header include

Previously, we included lib/fdio/util.h, but that header is being
removed. The declarations we need are in lib/fdio/fdio.h now.

Change-Id: I094b328766f1c67571044f85717b788eded1d142
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/1508635
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>
Commit-Queue: Adam Barth <261ec7bc01029d75f3df176083f56735e31b8587@chromium.org>

chromium/crashpad,chromium/crashpad,chromium/crashpad