scsi: hisi_sas: fix spelling mistake "digial" -> "digital"

There is a spelling mistake in literal string. Fix it.

Link: https://lore.kernel.org/r/20190916091706.32268-1-colin.king@canonical.comSigned-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -3539,7 +3539,7 @@ static const struct {
 	int		value;
 	char		*name;
 } hisi_sas_debugfs_loop_modes[] = {
-	{ HISI_SAS_BIST_LOOPBACK_MODE_DIGITAL, "digial" },
+	{ HISI_SAS_BIST_LOOPBACK_MODE_DIGITAL, "digital" },
 	{ HISI_SAS_BIST_LOOPBACK_MODE_SERDES, "serdes" },
 	{ HISI_SAS_BIST_LOOPBACK_MODE_REMOTE, "remote" },
 };