s390/qeth: fix initialization on old HW

I stumbled over an old OSA model that claims to support DIAG_ASSIST,
but then rejects the cmd to query its DIAG capabilities.

In the old code this was ok, as the returned raw error code was > 0.
Now that we translate the raw codes to errnos, the "rc < 0" causes us
to fail the initialization of the device.

The fix is trivial: don't bail out when the DIAG query fails. Such an
error is not critical, we can still use the device (with a slightly
reduced set of features).

Fixes: 742d4d40 ("s390/qeth: convert remaining legacy cmd callbacks")
Signed-off-by: NJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core_main.c

@@ -5026,10 +5026,8 @@ int qeth_core_hardsetup_card(struct qeth_card *card, bool *carrier_ok)
 	}
 	if (qeth_adp_supported(card, IPA_SETADP_SET_DIAG_ASSIST)) {
 		rc = qeth_query_setdiagass(card);
-		if (rc < 0) {
+		if (rc)
 			QETH_CARD_TEXT_(card, 2, "8err%d", rc);
-			goto out;
-		}
 	}
 
 	if (!qeth_is_diagass_supported(card, QETH_DIAGS_CMD_TRAP) ||