scsi: mpi3mr: Make some symbols static

scsi: mpi3mr: Make some symbols static

Fix the following warnings:

  drivers/scsi/mpi3mr/mpi3mr_os.c:24:5: warning: symbol 'prot_mask' was not declared. Should it be static?
  drivers/scsi/mpi3mr/mpi3mr_os.c:28:5: warning: symbol 'prot_guard_mask' was not declared. Should it be static?
  drivers/scsi/mpi3mr/mpi3mr_os.c:31:5: warning: symbol 'logging_level' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20210604071407.1360742-1-yangyingliang@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>