x/tools/go/internal/gccgoimporter: remove unused method

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

Change-Id: Ib8acac744a171b70f3f842f8f5f8c34064869383
Reviewed-on: https://go-review.googlesource.com/37604
Reviewed-by: Alan Donovan <adonovan@google.com>

go/internal/gccgoimporter/parser.go

@@ -900,10 +900,3 @@ func (p *parser) parsePackage() *types.Package {
 	p.pkg.MarkComplete()
 	return p.pkg
 }
-
-// InitData = { InitDataDirective } .
-func (p *parser) parseInitData() {
-	for p.tok != scanner.EOF {
-		p.parseInitDataDirective()
-	}
-}