mlx5: Fix HCA cap 2 query

Previously we were trying to set hca_cap_2 without checking if
sw_vhca_id_valid max value, which is the only settable value inside
hca_cap_2, and seeing that we dont have driver support for sw_vhca_id
yet there is no need to set hca_cap_2 at all, it is enough to query it.

Fixes: 7b959396ca6fae5635260131eedb9bc19f2726a3 ("mlx5: Introduce new destination type TABLE_TYPE")
MFC after: 3 days