scsi: qla2xxx: Make qla2x00_sysfs_write_nvram() easier to analyze

Modify the unlock statement such that it becomes easier for static
analyzers to analyze it. This patch does not change any functionality.

Cc: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>