net/mlx5: Fix XRC SRQ umem valid bits

Adapt XRC SRQ to the latest HW specification with fixed definition
around umem valid bits. The previous definition relied on a bit which
was taken for other purposes in legacy FW.

Fixes: bd371975

 ("net/mlx5: Update mlx5_ifc with DEVX UID bits")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>