scsi: libsas: Drop BLK_DEV_BSGLIB selection

SCSI_SAS_ATTRS already selects BLK_DEV_BSGLIB in drivers/scsi/Kconfig.
Remove selection in libsas/Kconfig.

Link: https://lore.kernel.org/r/20210723084624.2596297-1-guoqing.jiang@linux.dev


Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>