scsi: lpfc: Fix kernel Oops due to null pring pointers

scsi: lpfc: Fix kernel Oops due to null pring pointers

[ Upstream commit 5a9eeff57f340238c39c95d8e7e54c96fc722de7 ]

Driver is hitting null pring pointers in lpfc_do_work().

Pointer assignment occurs based on SLI-revision. If recovering after an
error, its possible the sli revision for the port was cleared, making the
lpfc_phba_elsring() not return a ring pointer, thus the null pointer.

Add SLI revision checking to lpfc_phba_elsring() and status checking to all
callers.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>