scsi: MAINTAINERS: Add a libsas entry

scsi: MAINTAINERS: Add a libsas entry

John has been reviewing libsas patches for years. And I have been
contributing to libsas for years and I am interested in reviewing and
testing libsas patches too. So add a libsas entry and add John and me as
reviewer.

Cc: John Garry <john.g.garry@oracle.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20230516110131.388634-1-yanaijie@huawei.com
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Acked-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>