scsi: be2iscsi: Mark beiscsi_attrs with static keyword

Fix the following sparse warning:

./be_main.c:167:25: warning: symbol 'beiscsi_attrs' was not declared. Should it be static?

Link: https://lore.kernel.org/r/1605339474-22329-1-git-send-email-zou_wei@huawei.com


Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>