10091 smatch fixes for ahci.c

@@ -6167,25 +6167,19 @@
             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);