IB/mlx5: Check supported flow table size

Check that the required flow table size is supported
by device. Return ENOMEM error if no space left.

In addition change the create flow table routine
to return ENOMEM instead of ENOSPC.

Fixes: 038d2ef8

 ('IB/mlx5: Add flow steering support')
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>