cmd/internal/gc: fix vet detected printf problems

Fixes #10805.

Change-Id: Ia77639e606a0c18fc53cba9749d92f325014025f
Reviewed-on: https://go-review.googlesource.com/10040
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/internal/gc/dcl.go b/src/cmd/internal/gc/dcl.go
index 08d2469..627556e 100644
--- a/src/cmd/internal/gc/dcl.go
+++ b/src/cmd/internal/gc/dcl.go
@@ -183,7 +183,7 @@
 	}
 
 	if ctxt == PEXTERN && s.Name == "init" {
-		Yyerror("cannot declare init - must be func", s)
+		Yyerror("cannot declare init - must be func")
 	}
 
 	gen := 0