net/mlx5: DR, For short chains of STEs, avoid allocating ste_arr dynamically

While creating rule, ste_arr is an array that is allocated at the start
of the function and freed at the end.
This memory allocation can sometimes lead to "hiccups" of up to 10ms.
However, the common use case is short chains of STEs. For such cases,
we can use a local buffer on stack instead.

Changes in v2:
  Use small local array for short rules, allocate dynamically for long rules

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>