scsi: myrb: Make some symblos static

This addresses the following sparse warning:

drivers/scsi/myrb.c:2229:27: warning: symbol 'myrb_template' was not
declared. Should it be static?
drivers/scsi/myrb.c:2318:31: warning: symbol 'myrb_raid_functions' was
not declared. Should it be static?
drivers/scsi/myrb.c:2492:6: warning: symbol 'myrb_err_status' was not
declared. Should it be static?

Link: https://lore.kernel.org/r/20200915084018.2826922-1-yanaijie@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>