scsi: megaraid: Make smp_affinity_enable static

scsi: megaraid: Make smp_affinity_enable static

This addresses the following sparse warning:

drivers/scsi/megaraid/megaraid_sas_base.c:80:5: warning: symbol
'smp_affinity_enable' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20200915083948.2826598-1-yanaijie@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>