[SCSI] qla2xxx: return SCSI_MLQUEUE_TARGET_BUSY when driver has detected rport error or race

If the fcport is not online then we do not want to block IO to all ports on
the host. We just want to stop IO on port not online, so we should be using
the SCSI_MLQUEUE_TARGET_BUSY return value.

For the case where we race with the rport memset initialization
we do not want the queuecommand to be called again so we can just use
SCSI_MLQUEUE_TARGET_BUSY for this.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>