cmd/goyacc: remove unused generated bindings
cmd/goyacc: remove unused generated bindings

Found with honnef.co/go/tools/cmd/unused (in CockroachDB).

Change-Id: I0e2f7ac6ad2a0fdc724928f316060f06c3261ece
Reviewed-on: https://go-review.googlesource.com/38178
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

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