scsi: lpfc: Validate hdwq pointers before dereferencing in reset/errata paths

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Validate hdwq pointers before dereferencing in reset/errata paths When the HBA is undergoing a reset or is handling an errata event, NULL ptr dereference crashes may occur in routines such as lpfc_sli_flush_io_rings(), lpfc_dev_loss_tmo_callbk(), or lpfc_abort_handler(). Add NULL ptr checks before dereferencing hdwq pointers that may have been freed due to operations colliding with a reset or errata event handler.