devlink: Add health set command

Add devlink health set command, in order to set configuration parameters
for a specific reporter.
Supported parameters are:
- graceful_period: Time interval between auto recoveries (in msec)
- auto_recover: Determines if the devlink shall execute recover upon
		receiving error for the reporter

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>