net/mlx5e: Allocate virtually contiguous memory for reps structures

Physical continuity is not necessary, and requested allocation size might
be larger than PAGE_SIZE.
Hence, use v-alloc/free API.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>