mlx4: Avoid leaking steering rules on flow creation error flow

If mlx4_ib_create_flow() attempts to create > 1 rules with the
firmware, and one of these registrations fail, we leaked the
already created flow rules.

One example of the leak is when the registration of the VXLAN ghost
steering rule fails, we didn't unregister the original rule requested
by the user, introduced in commit d2fce8a9 "mlx4: Set
user-space raw Ethernet QPs to properly handle VXLAN traffic".

While here, add dump of the VXLAN portion of steering rules
so it can actually be seen when flow creation fails.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>