scsi: fnic: Fix coccinelle warnings

Remove the duplicate copies of this simple function and use an
open-coded version.

drivers/scsi/fnic/fnic_debugfs.c:122:11-31: WARNING opportunity for simple_open, see also structure on line 223

Generated by: coccinelle/api/simple_open.cocci

Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>