IB/mlx5: Use the correct commands for UMEM and UCTX allocation

During testing the command format was changed to close a security
hole. Revise the driver to use the command format that will actually be
supported in GA firmware.

Both the UMEM and UCTX are intended only for use by the kernel and cannot
be executed using a general command.

Since the UMEM and CTX are not part of the general object the caps bits
were moved to be some log_xxx location in the general HCA caps.

The firmware code was adapted as well to match the above.

Fixes: a8b92ca1 ("IB/mlx5: Introduce DEVX")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>