scsi: zfcp: Handle event-lost notification for Version Change events

scsi: zfcp: Handle event-lost notification for Version Change events

As recovery for a lost Version Change event, trigger an Exchange Config
Data cmd to retrieve the current FW version.

Doing so requires process context (as eg. zfcp_qdio_sbal_get() might need
to sleep), so defer from tasklet context into a work item.

Link: https://lore.kernel.org/r/297c7be2944c3714863fcd22d531d910312d29f0.1603908167.git.bblock@linux.ibm.com
Suggested-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>