scsi: qla2xxx: Fix response queue count for Target mode.

Target mode initialization was not calculating response queue values
correctly resulting into one less MSI-X vector.

[mkp: fixed Fixes: hash]

Cc: <stable@vger.kernel.org>
Fixes: 093df737

 ("scsi: qla2xxx: Fix Target mode handling with Multiqueue changes.")
Signed-off-by: Michael Hernandez <michael.hernandez@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>