RDMA/efa: Expose minimum SQ size

The device reports the minimum SQ size required for creation.

This patch queries the min SQ size and reports it back to the userspace
library.

Link: https://lore.kernel.org/r/20200722140312.3651-3-galpress@amazon.com


Reviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Shadi Ammouri <sammouri@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>