bcachefs: Pretty-ify bch2_bkey_val_to_text()

Don't print out the ": " when there isn't a value to print.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/bkey_methods.c

@@ -269,7 +269,7 @@ void bch2_bkey_val_to_text(struct printbuf *out, struct bch_fs *c,
 {
 	bch2_bkey_to_text(out, k.k);
 
-	if (k.k) {
+	if (bkey_val_bytes(k.k)) {
 		pr_buf(out, ": ");
 		bch2_val_to_text(out, c, k);
 	}