cmd/dist: re-enable VFPv3 on openbsd/arm

The OpenBSD armv7 port has working VFPv3 these days - re-enable the VFP
detection code so that GOARM=7 is used by default on openbsd/arm.

Change-Id: I0271d81c048d2d55becd2803c19e5f1542076357
Reviewed-on: https://go-review.googlesource.com/c/154378Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

src/cmd/dist/util.go

@@ -397,9 +397,8 @@ func xgetgoarm() string {
 		// Conservative default for cross-compilation.
 		return "5"
 	}
-	if goos == "freebsd" || goos == "openbsd" {
+	if goos == "freebsd" {
 		// FreeBSD has broken VFP support.
-		// OpenBSD currently only supports softfloat.
 		return "5"
 	}