ide: hpt366: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that, in this particular case, I removed the "else: "
part from the comment. As we are now using Warning level 3:
-Wimplicit-fallthrough=3, this is what GCC is expecting to
find.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/ide/hpt366.c

@@ -574,7 +574,7 @@ static u8 hpt3xx_udma_filter(ide_drive_t *drive)
 		if (!HPT370_ALLOW_ATA100_5 ||
 		    check_in_drive_list(drive, bad_ata100_5))
 			return ATA_UDMA4;
-		/* else: fall through */
+		/* fall through */
 	case HPT372 :
 	case HPT372A:
 	case HPT372N:
@@ -601,7 +601,7 @@ static u8 hpt3xx_mdma_filter(ide_drive_t *drive)
 	case HPT374 :
 		if (ata_id_is_sata(drive->id))
 			return 0x00;
-		/* else: fall through */
+		/* fall through */
 	default:
 		return 0x07;
 	}