net: ax25: Fix fall-through warnings for Clang

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

---
Changes in RESEND:
- None. Resending now that net-next is open.

 net/ax25/af_ax25.c | 1 +
 1 file changed, 1 insertion(+)

index 269ee89d2c2b..2631efc6e359 100644
@@ -850,6 +850,7 @@ static int ax25_create(struct net *net, struct socket *sock, int protocol,
 		case AX25_P_ROSE:
 			if (ax25_protocol_is_registered(AX25_P_ROSE))
 				return -ESOCKTNOSUPPORT;
+			break;
 #endif
 		default:
 			break;

2.27.0