devlink: Add devlink health recover command

Add devlink health recover command which enables the user to initiate a
recovery on a reporter (if a recovery cb was supplied by the reporter).
This operation will increment the recoveries counter displayed in the
show command.
Example:
$ devlink health recover pci/0000:00:09.0 reporter tx

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