s390/qeth: don't mask TX errors on IQD devices

Current code suppresses debug entries when an TX buffer completes in
ERROR state with no error indication set in SBALF15.
This was introduced back with
commit 58490f18 ("qeth: HiperSockets SIGA retry support on CC=2.").
But qeth no longer retries after CC=2, and this sort of suppression
make no sense anymore. Remove it.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>