go/parser: simplify code (cleanup)

Change-Id: I0c8823b9c3c12f0f581b24db6a7aa5a0cd913224
Reviewed-on: https://go-review.googlesource.com/c/go/+/407537
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>

src/go/parser/parser.go

@@ -1307,8 +1307,7 @@ func (p *parser) tryIdentOrType() ast.Expr {
 	case token.MUL:
 		return p.parsePointerType()
 	case token.FUNC:
-		typ := p.parseFuncType()
-		return typ
+		return p.parseFuncType()
 	case token.INTERFACE:
 		return p.parseInterfaceType()
 	case token.MAP: