Add fp16 dependency, which is required for V8.
For context, see:
6196de89e3
Also fix pre-existing comment error in DEPS mentioning the wrong name
for fuchsia_gn_sdk_revision.
Change-Id: I35ca746380099544e7d3c783aa506bf73017a8f6
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/115290
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
