scsi: lpfc: fix remoteport access

The addition of a spinlock in lpfc_debugfs_nodelist_data() introduced
a bug that lets us not skip NULL pointers correctly, as noticed by
gcc-8:

drivers/scsi/lpfc/lpfc_debugfs.c: In function 'lpfc_debugfs_nodelist_data.constprop':
drivers/scsi/lpfc/lpfc_debugfs.c:728:13: error: 'nrport' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   if (nrport->port_role & FC_PORT_ROLE_NVME_INITIATOR)

This changes the logic back to what it was, while keeping the added
spinlock.

Fixes: 9e210178 ("scsi: lpfc: Synchronize access to remoteport via rport")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>