devlink: Add param command support

devlink: Add param command support

Add support for configuration parameters set and show.
Each parameter can be either generic or driver-specific.
The user can retrieve data on these configuration parameters by devlink
param show command and can set new value to a configuration parameter
by devlink param set command.
The configuration parameters can be set in different configuration
modes:
  runtime - set while driver is running, no reset required.
  driverinit - applied while driver initializes, requires restart
               driver by devlink reload command.
  permanent - written to device's non-volatile memory, hard reset
              required to apply.

New commands added:
  devlink dev param show [DEV name PARAMETER]
  devlink dev param set DEV name PARAMETER value VALUE
			    cmode { permanent | driverinit | runtime }

Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David Ahern <dsahern@gmail.com>