vxlan: correctly validate VXLAN ID against VXLAN_N_VID

[ Upstream commit 4e37d6911f36545b286d15073f6f2222f840e81c ]

The incorrect check caused an off-by-one error: the maximum VID 0xffffff
was unusable.

Fixes: d342894c5d2f ("vxlan: virtual extensible lan")
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index d4f495b..7e3b2e2 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2637,7 +2637,7 @@
 
 	if (data[IFLA_VXLAN_ID]) {
 		__u32 id = nla_get_u32(data[IFLA_VXLAN_ID]);
-		if (id >= VXLAN_VID_MASK)
+		if (id >= VXLAN_N_VID)
 			return -ERANGE;
 	}