scsi: libfc: fix seconds_since_last_reset miscalculation

Commit 540eb1ee ("scsi: libfc: fix seconds_since_last_reset calculation")
removed the use of 'struct timespec' from fc_get_host_stats(). This broke the
output of 'fcoeadm -s' after kernel 4.8-rc1.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: <stable@vger.kernel.org> # v4.8+
Fixes: 540eb1ee ("scsi: libfc: fix seconds_since_last_reset calculation")
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>