10091 smatch fixes for ahci.c

*** 6167,6191 ****
              kmem_zalloc(sizeof (ahci_event_arg_t), KM_SLEEP);
  
          ahci_portp->ahciport_event_args->ahciea_addrp =
              kmem_zalloc(sizeof (ahci_addr_t), KM_SLEEP);
  
-         if (ahci_portp->ahciport_event_args == NULL)
-                 goto err_case4;
- 
          /* Initialize the done queue */
          ahci_portp->ahciport_doneq = NULL;
          ahci_portp->ahciport_doneqtail = &ahci_portp->ahciport_doneq;
          ahci_portp->ahciport_doneq_len = 0;
  
          mutex_exit(&ahci_portp->ahciport_mutex);
  
          return (AHCI_SUCCESS);
  
- err_case4:
-         ddi_taskq_destroy(ahci_portp->ahciport_event_taskq);
- 
  err_case3:
          ahci_dealloc_cmd_list(ahci_ctlp, ahci_portp);
  
  err_case2:
          ahci_dealloc_rcvd_fis(ahci_portp);
--- 6167,6185 ----