Fix the following sparse warning:

drivers/scsi/bfa/bfad_bsg.c:140:1: warning: symbol
'bfad_iocmd_ioc_get_stats' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20200505073807.40332-1-yanaijie@huawei.comReported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>