Validation: Fix some function types. These were slightly mismatching the header types. They seemed to link fine despite producing some warnings in a tool. Bug: angleproject:4598 Change-Id: I19cfe4d87eca409c82a7c8cf25fff6f8a4c83ca9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2175057 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>