common/mlx5: add batch counter id offset

common/mlx5: add batch counter id offset

This commit is a part for the DV counter optimization.

The batch counter dcs id starts from 0x800000 and none batch counter
starts from 0. As currently, the counter is changed to be indexed by
pool index and the offset of the counter in the pool counters_raw array.
It means now the counter index is same for batch and none batch counter.
Add the 0x800000 batch counter offset to the batch counter index helps
indicate the counter index is from batch or none batch container pool.

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>