[PATCH][next] net: axienet: Fix fall-through warning for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding a fallthrough statement instead of just
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
JFYI: We had thousands of these sorts of warnings and now we are down
      to just 25 in linux-next. This is one of those last remaining
      warnings.

 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index b508c9453f40..e29ad9a86a3c 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1543,6 +1543,7 @@ static void axienet_validate(struct phylink_config *config,
 	case PHY_INTERFACE_MODE_MII:
 		phylink_set(mask, 100baseT_Full);
 		phylink_set(mask, 10baseT_Full);
+		fallthrough;
 	default:
 		break;
 	}

-- 
2.27.0