net: dsa: microchip: mark expected switch fall-through

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

This patch fixes the following warning:

drivers/net/dsa/microchip/ksz9477.c: In function ‘ksz9477_get_interface’:
drivers/net/dsa/microchip/ksz9477.c:1145:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (gbit)

      ^

drivers/net/dsa/microchip/ksz9477.c:1147:2: note: here
case 0:
^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable -Wimplicit-fallthrough.

---
 drivers/net/dsa/microchip/ksz9477.c | 1 +
 1 file changed, 1 insertion(+)

index f16e1d7d8615..c026d15721f6 100644
@@ -1144,6 +1144,7 @@ static phy_interface_t ksz9477_get_interface(struct ksz_device *dev, int port)
 		interface = PHY_INTERFACE_MODE_GMII;
 		if (gbit)
 			break;
+		/* fall through */
 	case 0:
 		interface = PHY_INTERFACE_MODE_MII;
 		break;

2.21.0

From: "Gustavo A. R. Silva" <[email protected]>
Date: Mon, 1 Apr 2019 15:34:49 -0500

Applied.