scsi: myrs: Make some symbols static

This addresses the following sparse warning:

drivers/scsi/myrs.c:1532:5: warning: symbol 'myrs_host_reset' was not
declared. Should it be static?
drivers/scsi/myrs.c:1922:27: warning: symbol 'myrs_template' was not
declared. Should it be static?
drivers/scsi/myrs.c:2036:31: warning: symbol 'myrs_raid_functions' was
not declared. Should it be static?
drivers/scsi/myrs.c:2046:6: warning: symbol 'myrs_flush_cache' was not
declared. Should it be static?

Link: https://lore.kernel.org/r/20200915084008.2826835-1-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>