RDMA/efa: Report host information to the device

The host info feature allows the driver to infrom the EFA device
firmware with system configuration for debugging and troubleshooting
purposes.

The host info buffer is passed as an admin command DMA mapped control
buffer, and is unmapped and freed once the command CQE is consumed.

Currently, the setting of host info is done for each device on its
probe. Failing to set the host info for the device shall not disturb the
probe flow, any errors will be discarded.

Link: https://lore.kernel.org/r/20200512152204.93091-3-galpress@amazon.com
Reviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Guy Tzalik <gtzalik@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>