RDMA/mlx5: Add init2init as a modify command

Missing INIT2INIT entry in the list of modify commands caused DEVX
applications to be unable to modify_qp for this transition state. Add the
MLX5_CMD_OP_INIT2INIT_QP opcode to the list of allowed DEVX opcodes.

Fixes: e662e14d

 ("IB/mlx5: Add DEVX support for modify and query commands")
Link: https://lore.kernel.org/r/20200513095550.211345-1-leon@kernel.org
Signed-off-by: Aharon Landau <aharonl@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>