net/mlx5: Read the TC mapping of all priorities on ETS query

When ETS configurations are queried by the user to get the mapping
assignment between packet priority and traffic class, only priorities up
to maximum TCs are queried from QTCT register in FW to retrieve their
assigned TC, leaving the rest of the priorities mapped to the default
TC #0 which might be misleading.

Fix by querying the TC mapping of all priorities on each ETS query,
regardless of the maximum number of TCs configured in FW.

Fixes: 820c2c5e ("net/mlx5e: Read ETS settings directly from firmware")
Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>