Revert "net/mlx5: Expose steering dropped packets counter"

This reverts commit 4fe1b3a5, which
exposes the steering dropped packets counter via debugfs. The upcoming
series will expose the counter via devlink health reporter instead
of debugfs.

Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>