net/mlx5: Move fw reset devlink param to fw reset code

Move the param registration and handling code into the fw reset code
as they are related to each other. No point in having the devlink param
registration done in separate file.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>