scsi: myrs: Make symbols DAC960_{GEM/BA/LP}_privdata static

This symbol is not used outside of myrs.c, so we can mark it static.

Link: https://lore.kernel.org/r/20210327073157.1786772-1-liushixin2@huawei.com


Signed-off-by: Shixin Liu <liushixin2@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>