scsi: zfcp: do not trace pure benign residual HBA responses at default level

Since quite a while, Linux issues enough SCSI commands per scsi_device
which successfully return with FCP_RESID_UNDER, FSF_FCP_RSP_AVAILABLE,
and SAM_STAT_GOOD.  This floods the HBA trace area and we cannot see
other and important HBA trace records long enough.

Therefore, do not trace HBA response errors for pure benign residual
under counts at the default trace level.

This excludes benign residual under count combined with other validity
bits set in FCP_RSP_IU, such as FCP_SNS_LEN_VAL.  For all those other
cases, we still do want to see both the HBA record and the corresponding
SCSI record by default.

Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: a54ca0f6

 ("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
Cc: <stable@vger.kernel.org> #2.6.37+
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>