devlink: Rename devlink health attributes

Rename devlink health attributes for better reflect the attributes use.
Add COUNT prefix on error counter attribute and recovery counter
attribute.

Fixes: 7afe335a ("devlink: Add health get command")
Signed-off-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>