Revert "[fidl][overnet] Allow extra C++ dependencies"

This reverts commit f07f6271d59b6123bcccbfd86352959b3f7e31bb.

Reason for revert: Had Code-Review -1 before landing.

Original change's description:
> [fidl][overnet] Allow extra C++ dependencies
> 
> Allows additional C++ dependencies to be listed for FIDL libraries, in
> turn enabling additional code generation options.
> 
> Test: utilized on an upcoming garnet CL
> 
> Change-Id: I13a6063411ebfbb76d6ce3d02c1f98f5f5e92007

TBR=abarth@google.com,ctiller@google.com,pascallouis@google.com

Change-Id: Ic62f59620275ac3e2628a5bc1423bf309b574a84
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
2 files changed