scsi: arcmsr: Update driver version to v1.50.00.02-20200819

Update driver version to v1.50.00.02-20200819.

Link: https://lore.kernel.org/r/b41f9af781bc36f4e5f82fccabc86ebbd0e587f8.camel@areca.com.tw


Signed-off-by: ching Huang <ching2048@areca.com.tw>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>