x/tools/cmd/goyacc: remove unused function.
x/tools/cmd/goyacc: remove unused function.

Found with honnef.co/go/tools/cmd/unused.

Change-Id: Iad26e1ae1dbeb29a3223279eccc4ba6f6bb48bd6
Reviewed-on: https://go-review.googlesource.com/37631
Reviewed-by: Alan Donovan <7069e9552f9d110b0a0f326b96f22f63fb99dfc1@google.com>

syreclabs/go-tools,syreclabs/go-tools,syreclabs/go-tools,syreclabs/go-tools,golang/tools,syreclabs/go-tools,golang/tools,golang/tools,syreclabs/go-tools,golang/tools,golang/tools