libata: clear ehi description after initial host report

ehi description field is used to carry LLD specific controller
description.  Sometimes, it's used without clearing before and LLD
description gets printed with exception information one more time.
Clear after printing.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 519ce58..db760e2 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6773,13 +6773,14 @@
 		xfer_mask = ata_pack_xfermask(ap->pio_mask, ap->mwdma_mask,
 					      ap->udma_mask);
 
-		if (!ata_port_is_dummy(ap))
+		if (!ata_port_is_dummy(ap)) {
 			ata_port_printk(ap, KERN_INFO,
 					"%cATA max %s %s\n",
 					(ap->flags & ATA_FLAG_SATA) ? 'S' : 'P',
 					ata_mode_string(xfer_mask),
 					ap->link.eh_info.desc);
-		else
+			ata_ehi_clear_desc(&ap->link.eh_info);
+		} else
 			ata_port_printk(ap, KERN_INFO, "DUMMY\n");
 	}