scsi: ibmvfc: Fix missing cast of ibmvfc_event pointer to u64 handle

scsi: ibmvfc: Fix missing cast of ibmvfc_event pointer to u64 handle

Commit 2aa0102c6688 ("scsi: ibmvfc: Use correlation token to tag commands")
sets the vfcFrame correlation token to the pointer handle of the associated
ibmvfc_event. However, that commit failed to cast the pointer to an
appropriate type which in this case is a u64. As such sparse warnings are
generated for both correlation token assignments.

 ibmvfc.c:2375:36: sparse: incorrect type in argument 1 (different base types)
 ibmvfc.c:2375:36: sparse: expected unsigned long long [usertype] val
 ibmvfc.c:2375:36: sparse: got struct ibmvfc_event *[assigned] evt

Add the appropriate u64 casts when assigning an ibmvfc_event as a
correlation token.

Link: https://lore.kernel.org/r/20210106203721.1054693-1-tyreld@linux.ibm.com
Fixes: 2aa0102c6688 ("scsi: ibmvfc: Use correlation token to tag commands")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>