An hba-wide lock is taken in the nvme io completion routine. The lock
covers null'ing of the nrport pointer in the cmd structure.

The nrport member isn't necessary. After extracting the pointer from the
command, the pointer was dereferenced to get the fc discovery node
pointer. But the fc discovery node pointer is alrady in the command
structure so the dereferrence was unnecessary.

Eliminated the nrport structure member and its use, which also eliminates
the port-wide lock.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>